Rick's Free Auto Repair Advice

Why is my ABS TCS light on

How to fix an ABS or TCS light on

Many early 2000 model GM vehicles use the Bosch 5.3 ABS TCS unit. If you have an ABS TCS light on with low power, read this post. In addition to ABS, the also controls the traction control. The system watches the wheel speed sensors and if it sees a skid, If so, it operates the ABS. Ttraction control also uses a steering angle sensor a yaw sensor and an accelerometer. The system compares the angle of the steering wheel (the direction you’re steering) to the yaw sensor (the direction you’re actually going) and the acceleration and determines whether the vehicle is losing control. If so, the ABS TCS unit can apply the breaks to bring the vehicle back on track or it can cut engine power, or a combination of both. I

GM has had many problems with the steering angle sensor.

As with any warning light, your first step is to pull the trouble codes. That’ll tell you what set off the light.

C0035 ………………. Left Front Wheel Speed Circuit Malfunction
C0036 …………. Left Front Wheel Speed Circuit Range/Performance
C0040 ……………… Right Front Wheel Speed Circuit Malfunction
C0041 ………… Right Front Wheel Speed Circuit Range/Performance
C0045 ……………….. Left Rear Wheel Speed Circuit Malfunction
C0046 ………….. Left Rear Wheel Speed Circuit Range/Performance
C0050 ………………. Right Rear Wheel Speed Circuit Malfunction
C0051 …………. Right Rear Wheel Speed Circuit Range/Performance
C0060 ………… Left Front ABS Solenoid No. 1 Circuit Malfunction
C0065 ………… Left Front ABS Solenoid No. 2 Circuit Malfunction
C0070 ……….. Right Front ABS Solenoid No. 1 Circuit Malfunction
C0075 ……….. Right Front ABS Solenoid No. 2 Circuit Malfunction
C0080 …………. Left Rear ABS Solenoid No. 1 Circuit Malfunction
C0085 …………. Left Rear ABS Solenoid No. 2 Circuit Malfunction
C0090 ………… Right Rear ABS Solenoid No. 1 Circuit Malfunction
C0095 ………… Right Rear ABS Solenoid No. 2 Circuit Malfunction
C0100 (2) ………….. Rear ABS Solenoid No. 1 Circuit Malfunction
C0105 (2) ………….. Rear ABS Solenoid No. 2 Circuit Malfunction
C0110 …………………………. Pump Motor Circuit Malfunction
C0121 ………………………… Valve Relay Circuit Malfunction
C0131 (3) ………….. ABS/TCS System Pressure Circuit Malfunction
C0132 (3) …….. ABS/TCS System Pressure Circuit Range/Performance
C0141 (4) ………….. Left TCS Solenoid No. 1 Circuit Malfunction
C0146 (4) ………….. Left TCS Solenoid No. 2 Circuit Malfunction
C0151 (4) …………. Right TCS Solenoid No. 1 Circuit Malfunction
C0156 (4) …………. Right TCS Solenoid No. 2 Circuit Malfunction
C0161 ………………… ABS/TCS Brake Switch Circuit Malfunction
C0166 (2) …………… TCS Priming Line Valve Circuit Malfunction
C0171 (2) …………………. TCS Pilot Valve Circuit Malfunction
C0181 (2) …………. Throttle Reduction Motor Circuit Malfunction
C0182 (2) ……. Throttle Reduction Motor Circuit Range/Performance
C0186 (3) ……………. Lateral Accelerometer Circuit Malfunction
C0187 (3) ………. Lateral Accelerometer Circuit Range/Performance
C0196 (3) ……………………….. Yaw Rate Circuit Malfunction
C0197 (3) ………………….. Yaw Rate Circuit Range/Performance
C0235 ……………………… TCS RPM Signal Circuit Malfunction
C0236 ……………………… TCS RPM Signal Circuit Malfunction
C0237 ……………………… TCS RPM Signal Circuit Malfunction
C0238 (2) …… TCS Throttle Position Sensor Comparison Malfunction
C0239 (2) ……………… TCS Spark Retard Monitoring Malfunction
C0240 ……………………….. PCM Traction Control Not Allowed
C0241 ………………. PCM Indicated Requested Torque Malfunction
C0244 ……………………….. PWM Delivered Torque Malfunction
C0245 ……………………… Wheel Speed Sensor Frequency Error
C0252 (3) ……………. Active Brake Control Sensors Uncorrelated
C0253 (3) …………………………………… Centering Fault
C0266 (2) …………………………. ADS Controller Malfunction
C0550 ………………………………………. ECU Malfunction
C0710 (3) ………………… Steering Position Signal Malfunction
C0870 (3) ……. BPMV Pressure Sensor Reference Circuit Malfunction
C0875 (3) ….. Yaw/Lateral Accelerometer Sensor Circuit Malfunction
C0896 ……………………….. Device Voltage Range/Performance
C0901 (2) …………………………… Device No. 2 Voltage Low
P1504 ……………………… TCS RPM Signal Circuit Malfunction
P1571 ………………. PCM Indicated Requested Torque Malfunction
P1689 ……………………….. PWM Delivered Torque Malfunction
PXXXX …………………………………………………. ( 5)
U1650 (3) …… Chassis System Dedicated Bus Controller Malfunction
U1651 (3) ………. Chassis System Dedicated Bus Sensor Malfunction
UXXXX …………………………………………………. ( 6)
(1) – See DIAGNOSTIC TESTS under appropriate BODY CONTROL MODULES
article in ACCESSORIES & EQUIPMENT.
(2) – Camaro and Firebird only.
(3) – Intrigue only.
(4) – Grand Prix and Intrigue only.
(5) – For any DTC beginning with the letter “P”, except P1504, P1571
or P1689, see appropriate SELF-DIAGNOSTICS article in ENGINE
PERFORMANCE.
(6) – For any DTC beginning with the letter “U” except U1650 and
U1651, see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2 DEVICE
under appropriate BODY CONTROL MODULES article in ACCESSORIES
& EQUIPMENT.
___________________________________________________________________________________________________________________________________________
.
DTC C0035, C0036, C0040, C0041, C0045, C0046, C0050 & C0051:
WHEEL SPEED SENSOR CIRCUIT
Circuit Description
DTC definitions:
* DTC C0035 – Left front wheel speed circuit malfunction.
* DTC C0036 – Left front wheel speed circuit range/performance.
* DTC C0040 – Right front wheel speed circuit malfunction.
* DTC C0041 – Right front wheel speed circuit
range/performance.
* DTC C0045 – Left rear wheel speed circuit malfunction.
* DTC C0046 – Left rear wheel speed circuit range/performance.
* DTC C0050 – Right rear wheel speed circuit malfunction.
* DTC C0051 – Right rear wheel speed circuit range/performance.
Speed sensor used on this vehicle is a multiple pole magnetic
pickup. Sensor produces an AC signal that EBCM uses frequency from to
calculate wheel speed.

DTC C0035, C0040, C0045 or C0050 sets when ignition is on and EBCM detects a short to voltage (wheel speed sensor signal circuit
greater than 4.25 volts) or an open (wheel speed sensor signal circuit voltage is greater than 4.25 volts and wheel speed sensor return
circuit voltage is less than 0.75 volt) for more than 0.02 second. DTC C0036, C0041, C0046 or C0051 sets when all of the
following conditions exists for 10 milliseconds: * Suspect wheel speed equals zero.
* Other wheel speeds are greater than 25 MPH for 0.01 second.
* Suspect wheel equals zero during drive-off, and other
wheels are greater than 7.5 MPH.
* Short to ground (wheel speed sensor signal circuit
is shorted to ground).
* Deviation of two wheel speeds at either side of vehicle
is greater than 4 MPH, or at front axle, greater than
6 MPH for a time period of 10 to 20 seconds.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Install scan tool. Turn ignition on. Set up scan tool snap
shot feature to trigger for this DTC. Drive vehicle at a speed greater
than 5 MPH. If DTC resets, go to next set. If DTC does not reset, see
DIAGNOSTIC AIDS.
3) Raise and support vehicle. Disconnect wheel speed sensor
connector. Measure resistance across wheel speed sensor. If resistance
is 800-1600 ohms, go to next step. If resistance is not 800-1600 ohms,
go to step 8).
4) Spin wheel. Measure AC voltage across wheel speed sensor.
If AC voltage is greater than 100 millivolts, go to next step. If AC
voltage is not greater than 100 millivolts, go to step 8).
5) Check wheel speed sensor connector for poor connections.
If problem was found, repair as necessary. After repairs, go to step
10). If problem was not found, go to next step.
6) Disconnect EBCM connector. Install Universal Pinout Box
(J-39700) using Adapter Cable (J-39700-530) to EBCM harness connector
only. Check wheel speed sensor circuits for open, short to ground,
short to voltage or shorted together. If problem was found, repair as
necessary. After repairs, go to step 10). If problem was not found, go
to next step.
7) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 10). If problem
was not found, go to step 9).
8) Replace wheel speed sensor. See WHEEL SPEED SENSOR under
REMOVAL & INSTALLATION. After repairs, go to step 10).
9) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
10) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.
If ABS/TCS indicator illuminates only during moist
conditions, inspect wheel speed sensor circuitry for signs of water
intrusion. Clear DTCs and simulate effects of water intrusion using a
saltwater solution. If DTC resets, replace suspect wiring harness.
Possible cause of DTCs C0036, C0041, C0046 and C0051 is
electrical noise on wheel speed sensor harness wiring. Electrical
noise could result from wheel speed sensor wires being routed to close
to high energy ignition system components, such as spark plug wires.

DTC C0060, C0065, C0070, C0075, C0080, C0085, C0090 & C0095:
SOLENOID CIRCUIT MALFUNCTION
Circuit Description
DTC definitions:
* DTC C0060 – Left front ABS solenoid No. 1 circuit malfunction
* DTC C0065 – Left front ABS solenoid No. 2 circuit malfunction
* DTC C0070 – Right front ABS solenoid No. 1 circuit
malfunction
* DTC C0075 – Right front ABS solenoid No. 2 circuit
malfunction
* DTC C0080 – Left rear ABS solenoid No. 1 circuit malfunction
* DTC C0085 – Left rear ABS solenoid No. 2 circuit malfunction
* DTC C0090 – Right rear ABS solenoid No. 1 circuit malfunction
* DTC C0095 – Right rear ABS solenoid No. 2 circuit malfunction
Inlet and outlet valve solenoid circuits are supplied with
battery power when ignition is on. EBCM controls valve functions by
grounding circuit when necessary.
DTC sets when EBCM detects open, short to ground or short to
voltage in solenoid coil or circuit.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Using scan tool, clear DTC. Remove scan tool from DLC.
Carefully drive vehicle above 8 MPH for several minutes. Turn ignition
off. Install scan tool. Turn ignition on, engine off. Using scan tool
in DIAGNOSTIC TROUBLE CODES, check for DTCs. If DTC resets as a
current DTC, go to next step. If DTC does not reset as a current DTC,
see INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.
3) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
4) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Solenoid valve circuit and solenoid coil are internal to
EBCM. No part of solenoid circuit is diagnosable external to EBCM. DTC
sets when there is a malfunction in solenoid circuit internal to EBCM
only.

DTC C0100 & C0105: REAR ABS SOLENOID NO. 1 OR NO. 2 CIRCUIT
MALFUNCTION (CAMARO & FIREBIRD)
Circuit Description
Inlet and outlet valve solenoid circuits are supplied with
battery power when ignition is on. EBCM controls valve functions by
grounding circuit when necessary.
DTC sets when EBCM detects open, short to ground or short to
voltage in solenoid coil or circuit.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Using scan tool, clear DTC. Remove scan tool from DLC.
Carefully drive vehicle above 8 MPH for several minutes. Turn ignition
off. Install scan tool. Turn ignition on, engine off. Using scan tool
in DIAGNOSTIC TROUBLE CODES, check for DTCs. If DTC resets as a
current DTC, go to next step. If DTC does not reset as a current DTC,
see INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.
3) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
4) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Solenoid valve circuit and solenoid coil are internal to
EBCM. No part of solenoid circuit is diagnosable external to EBCM. DTC
sets when there is a malfunction in solenoid circuit internal to EBCM
only.

DTC C0110: PUMP MOTOR CIRCUIT MALFUNCTION
Circuit Description
Pump motor is an integral part of BPMV, while pump motor
relay is integral to EBCM. Pump motor relay is not engaged during
normal system operation. When ABS or TCS operation is required, EBCM
activates pump motor relay and battery power is provided to the pump
motor.
DTC sets when pump motor voltage is not present 60
milliseconds after activation of pump motor relay, pump motor voltage
is present for more than 2.5 seconds with no activation of pump motor
relay or pump motor voltage is not present for 40 milliseconds after
pump motor relay is commanded off.
Diagnosis
NOTE: Power supply to Red wire at EBCM connector terminal No. 13
varies with vehicle type. Applications are as follows: ABS
BAT 1 fuse (40-amp) – Camaro and Firebird, fusible link –
Grand Prix and Intrigue (federal emissions) or ABS MOTOR fuse
(40-amp) – Intrigue (California emissions).
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM connector. Install
Universal Pinout Box (J 39700) using Cable Adapter (J 39700-25) to
EBCM harness connector only. Check both ground circuits of EBCM
including EBCM ground for high resistance or open. Check battery
voltage circuits for open, high resistance, or short to ground. If
problem was found, repair as necessary. After repairs, go to step 8).
If problem was not found, go to next step.
3) Disconnect pump motor harness pigtail connector of BPMV.
Measure resistance between each pump motor control circuit and housing
of BPMV at pump motor pigtail connector of BPMV. If resistance is less
than 5 ohms, go to next step. If resistance is not less than 5 ohms,
go to step 5).
4) Check BPMV connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 8). If problem
was not found, go to step 6).
5) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 8). If problem
was not found, go to step 7).
6) Replace BPMV. See BRAKE PRESSURE MODULATOR VALVE under
REMOVAL & INSTALLATION. After repairs, go to step 8).
7) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
8) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0121: VALVE RELAY CIRCUIT MALFUNCTION
Circuit Description
Solenoid valve relay supplies power to solenoid valve coils
in EBCM. Solenoid valve relay, located in EBCM, is activated whenever
ignition is on and no faults are present. Solenoid valve relay remains
engaged until ignition is turned off or a failure is detected.
DTC sets anytime solenoid valve relay is commanded on and
EBCM does not see battery voltage at solenoid valves or anytime EBCM
commands solenoid valve relay off and battery voltage is still present
at solenoid valves.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Install scan tool. Turn ignition on, engine off. Using
scan tool, clear DTCs. If DTC resets, go to next step. If DTC does not
reset, see DIAGNOSTIC AIDS.
3) Disconnect EBCM connector. Install Universal Pinout Box (J
39700) using Cable Adapter (J 39700-25) to EBCM harness connector
only. Check battery voltage circuit (universal pinout box terminals
No. 13 and 14) for open, high resistance, or short to ground. If
problem was found, repair as necessary. After repair, go to step 5).
If problem was not found, go to next step.
4) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
5) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation. Solenoid valve relay
is an integral part of EBCM and is not serviced separately.

DTC C0131: ABS/TCS SYSTEM PRESSURE CIRCUIT MALFUNCTION
(INTRIGUE)
Circuit Description
EBCM uses input from brake pressure sensor for more accurate
control during a Vehicle Stability Enhancement System (VSES) event.
DTC sets when voltage at pressure sensor signal output to
EBCM falls outside 0.25 V – 4.75 volt range for more than 100
milliseconds. DTC C0870 must not be set and vehicle speed must be
greater than 24 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM. Install Universal
Pinout Box (J 39700) with Cable Adapter (J 39700-530) between EBCM and
EBCM connector. Turn ignition on, engine off. Using DVOM, measure
voltage between universal pinout box terminals No. 17 (Orange wire)
and No. 15 (Black/White wire). If voltage is 0.25-4.75 volts, see
DIAGNOSTIC AIDS. If voltage is not 0.25-4.75 volts, go to next step.
3) Turn ignition off. Disconnect brake pressure sensor. Turn
ignition on, engine off. Using DVOM, measure voltage between universal
pinout box terminals No. 17 (Orange wire) and No. 15 (Black/White
wire). If voltage is less than 2.5 volts, go to next step. If voltage
is not less than 2.5 volts, go to step 9).
4) Turn ignition off. Connect fused jumper wire (3 amp)
between Orange wire of the brake pressure sensor (signal circuit) and
Gray wire (5-volt reference circuit) of brake pressure sensor. Turn
ignition on, engine off. Using DVOM, measure voltage between universal
pinout box terminals No. 17 (Orange wire) and No. 15 (Black/White
wire). If voltage is greater than 4.75 volts, go to next step. If
voltage is not greater than 4.75 volts, go to step 6).
5) Turn ignition off. Disconnect fused jumper wire. Turn
ignition on, engine off. Measure voltage between Gray wire (5-volt
reference circuit) of brake pressure sensor and ground. If voltage is
greater than 5.0 volts, go to step 7). If voltage is not greater than
5.0 volts, go to step10).
6) Check Gray wire (5-volt reference circuit) of brake
pressure sensor for short to ground. If problem was found, repair as
necessary. After repairs, go to step 15). If problem was not found, go
to step 8).
7) Check Gray wire (5-volt reference circuit) of brake
pressure sensor for short to voltage. If problem was found, repair as
necessary. After repairs, go to step 15). If problem was not found, go
to step 12).
8) Check Orange wire (signal circuit) of brake pressure
sensor for short to ground, high resistance or open. If problem was
found, repair as necessary. After repairs, go to step 15). If problem
was not found, go to step 12).
9) Check Orange wire (signal circuit) of brake pressure
sensor for short to voltage, high resistance or open. If problem was
found, repair as necessary. After repairs, go to step 15). If problem
was not found, go to step 12).
10) Check Gray/Black wire (ground circuit) of brake pressure
sensor for high resistance or open. If problem was found, repair as
necessary. After repairs, go to step 15). If problem was not found, go
to next step.
11) Check brake pressure sensor connector for poor
connections. If problem was found, repair as necessary. After repairs,
go to step 15). If problem was not found, go to step 13).
12) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 15). If problem
was not found, go to step 14).
13) Replace brake pressure sensor. See
BRAKE PRESSURE SENSOR (INTRIGUE) under REMOVAL & INSTALLATION. After
repairs, go to step 15).
14) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
15) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0132: ABS/TCS SYSTEM PRESSURE CIRCUIT RANGE/PERFORMANCE
(INTRIGUE)
Circuit Description
During calibration of offset of pressure sensor signal,
pressure sensor signal offset value must be -217.5 to 217.5 psi (-5.29
to 5.29 kg/cm

). Pressure sensor is also monitored for sensitivity via
a correlation between estimated vehicle deceleration and pressure
sensor signal. This is monitored over the course of numerous straight
line non ABS braking stops.
DTC sets when sensor signal offset value is out of range for
more than one second with brake pedal applied, ABS pump is not on and
vehicle speed is greater than 25 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM. Install Universal
Pinout Box (J 39700) with Cable Adapter (J 39700-530) between EBCM and
EBCM connector. Turn ignition on, engine off. Using DVOM, measure
voltage between universal pinout box terminals No. 17 (Orange wire)
and No. 15 (Black/White wire). If voltage is 0.25-4.75 volts, see
DIAGNOSTIC AIDS. If voltage is not 0.25-4.75 volts, go to next step.
3) Turn ignition off. Disconnect brake pressure sensor. Turn
ignition on, engine off. Using DVOM, measure voltage between universal
pinout box terminals No. 17 (Orange wire) and No. 15 (Black/White
wire). If voltage is less than 0.25 volt, go to next step. If voltage
is not less than 0.25 volt, go to step 10).
4) Turn ignition off. Connect fused jumper wire (3 amp)
between Gray wire (5-volt reference circuit) of the brake pressure
sensor and signal circuit (Orange wire) of brake pressure sensor. Turn
ignition on, engine off. Using DVOM, measure voltage between universal
pinout box terminals No. 17 (Orange wire) and No. 15 (Black/White
wire). If voltage is greater than 0.25 volt, go to next step. If
voltage is not greater than 0.25 volt, go to step 8).
5) Disconnect fused jumper wire. Measure voltage between Gray
wire (5-volt reference circuit) of brake pressure sensor and
Gray/Black wire (ground circuit) of brake pressure sensor. If voltage
is less than 5 volts, go to next step. If voltage is not less than 5
volts, go to step 7).
6) Turn ignition off. Disconnect negative battery cable.
Measure resistance of Gray/Black wire (ground circuit) between brake
pressure sensor and ground. If resistance is 0-5 ohms, go to step 12).
If resistance is not 0-5 ohms, go to step 11).
7) Check Gray wire (5-volt reference circuit) of brake
pressure sensor for short to voltage. If problem was found, repair as
necessary. After repairs, go to step 16). If problem was not found, go
to step 13).
8) Check Gray wire (5-volt reference circuit) of brake
pressure sensor for short to ground, high resistance, or open. If
problem was found, repair as necessary. After repairs, go to step 16).
If problem was not found, go to next step.
9) Check Orange wire (signal circuit) of brake pressure
sensor for short to ground, high resistance, or open. If problem was
found, repair as necessary. After repairs, go to step 16). If problem
was not found, go to step 13).
10) Check Orange wire (signal circuit) of brake pressure
sensor for short to voltage. If problem was found, repair as
necessary. After repairs, go to step 16). If problem was not found, go
to step 13).
11) Disconnect EBCM. Check Gray/Black wire (ground circuit)
of brake pressure sensor for high resistance or open. If problem was
found, repair as necessary. After repairs, go to step 16). If problem
was not found, go to step 13).
12) Check brake pressure sensor connector for poor
connections. If problem was found, repair as necessary. After repairs,
go to step 16). If problem was not found, go to step 14).
13) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 16). If problem
was not found, go to step 15).
14) Replace brake pressure sensor. See
BRAKE PRESSURE SENSOR (INTRIGUE) under REMOVAL & INSTALLATION. After
repairs, go to step 16).
15) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
16) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Probable causes are malfunctioning pressure sensor or
malfunctioning EBCM.

DTC C0141, C0146, C0151 & C0156: TCS SOLENOID CIRCUIT
MALFUNCTION (GRAND PRIX & INTRIGUE)
Circuit Description
DTC definitions:
* DTC C0141 – Left TCS solenoid No. 1 circuit malfunction.
* DTC C0146 – Left TCS solenoid No. 2 circuit malfunction.
* DTC C0151 – Right TCS solenoid No. 1 circuit malfunction.
* DTC C0156 – Right TCS solenoid No. 2 circuit malfunction.
Isolation and prime valve solenoid circuits are supplied with
battery power when ignition is on. EBCM controls valve functions by
grounding circuit when necessary.
DTC sets when EBCM detects an open in solenoid coil or
circuit, short to ground in solenoid coil or circuit or short to
voltage in solenoid coil or circuit.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Using scan tool, clear DTC. Remove scan tool from DLC.
Carefully drive vehicle above 8 MPH for several minutes. Turn ignition
off. Install scan tool. Turn ignition switch on, engine off. Using
scan tool in DIAGNOSTIC TROUBLE CODES mode, check for DTCs. If DTC
resets, go to next step. If DTC does not reset, see DIAGNOSTIC AIDS.
3) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
4) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Solenoid valve circuit and solenoid coil are internal to
EBCM. No part of solenoid circuit is diagnosable external to EBCM. DTC
sets when there is a malfunction in solenoid circuit internal to EBCM
only.

DTC C0161: ABS/TCS BRAKE SWITCH CIRCUIT MALFUNCTION
Circuit Description
Stoplight switch is a normally open switch, when brake pedal
is depressed, EBCM will sense battery voltage. This allows EBCM to
determine state of brake lights.
DTC sets when EBCM detects battery voltage at all times, EBCM
never detects battery voltage from stoplight switch or both brake
lights are faulty.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Press brake pedal. Using scan tool, observe BRAKE SWITCH
STATUS parameter in ABS data list. If BRAKE SWITCH STATUS parameter
displays APPLIED, go to step 4). If BRAKE SWITCH STATUS parameter does
not display APPLIED, go to next step.
3) Check signal circuit (Light Blue wire for Camaro and
Firebird, or White wire for Grand Prix and Intrigue) of stoplight
switch for open. If problem was found, repair as necessary. After
repairs, go to step 15). If problem was not found, go to step 11).
4) Press brake pedal. If all stoplights are off, go to next
step. If all stoplights are not off, go to step 7).
5) Check feed circuit (Orange wire) of stoplights for open or
high resistance. If problem was found, repair as necessary. After
repairs, go to step 15). If problem was not found, go to next step.
6) Check ground circuit (Black wire) of stoplights for open
or high resistance If problem was found, repair as necessary. After
repairs, go to step 15). If problem was not found, see DIAGNOSTIC
AIDS.
7) Press brake pedal. Using scan tool, observe BRAKE SWITCH
STATUS parameter. If BRAKE SWITCH STATUS parameter changes state, see
DIAGNOSTIC AIDS. If BRAKE SWITCH STATUS parameter does not change
state, go to next step.
8) Turn ignition off. Inspect stoplight switch and adjust
and/or calibrate if needed. See STOPLIGHT SWITCH under ADJUSTMENTS. If
problem was found, repair as necessary. After repairs, go to step 15).
If problem was not found, go to next step.
9) Turn ignition off. Disconnect stoplight switch connector.
Turn ignition on, engine off. Using scan tool, observe BRAKE SWITCH
STATUS parameter. If scan tool displays RELEASED, go to step 11). If
scan tool does not display RELEASED, go to next step.
10) Check stoplight signal circuit (Light Blue wire for
Camaro and Firebird, or White wire for Grand Prix and Intrigue) for
short to voltage. If problem was found, repair as necessary. After
repairs, go to step 15). If problem was not found, go to step 12).
11) Check stoplight switch connector for poor connections. If
problem was found, repair as necessary. After repairs, go to step 15).
If problem was not found, go to step 13).
12) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 15). If problem
was not found, go to step 14).
13) Replace stoplight switch. See STOPLIGHT SWITCH under
REMOVAL & INSTALLATION. After repairs, go to step 15).
14) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
15) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0166 & C0171: TCS PRIMING LINE OF PILOT VALVE CIRCUIT
MALFUNCTION (CAMARO & FIREBIRD)
Circuit Description
Master cylinder isolation valve, or TCS prime solenoid
circuits are supplied with battery power when ignition is on. EBCM
controls valve functions by grounding circuit when necessary.
DTC sets when EBCM senses an open, short to ground, or short
to voltage in circuit.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Using scan tool, clear DTC. Remove scan tool from DLC.
Carefully drive vehicle above 8 MPH for several minutes. Turn ignition
off. Install scan tool. Turn ignition switch on, engine off. Using
scan tool in DIAGNOSTIC TROUBLE CODES mode, check for DTCs. If DTC
resets, go to next step. If DTC does not reset, see
DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
3) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
4) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.

DTC C0181: THROTTLE REDUCTION MOTOR CIRCUIT MALFUNCTION
(CAMARO & FIREBIRD)
Circuit Description
Identifies an adjuster assembly motor circuit that is shorted
to ground, shorted to voltage, or open circuit. This malfunction will
not allow adjuster assembly motor to be controlled at commanded
current rate or will cause driver circuit to allow current directly to
ground.
DTC sets anytime EBCM detects an open, short to ground, or
short to voltage with ignition on.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect accelerator control and
adjuster connector. Disconnect all cables from accelerator control and
adjuster. Rotate adjuster by hand fully, then release and allow to
return to stop. Repeat this procedure three times. Zero leads on DVOM.
Using DVOM, measure resistance between accelerator control and
adjuster connector terminals “A” and “B”. If resistance is 0.5-10
ohms, go to step 4). If resistance is not 0.5-10 ohms, go to next
step.
3) Replace accelerator control and adjuster. See
ADJUSTER ASSEMBLY (CAMARO & FIREBIRD) under REMOVAL & INSTALLATION.
After repairs, go to step 19).
4) Disconnect Accelerator & Servo Module (ASM) connector.
Using a DVOM, measure resistance between ASM connector terminals No.
22 (White wire) and No. 28 (Black/White wire). If resistance is
infinite, go to step 6). If resistance is not infinite, go to next
step.
5) Repair short to ground in White wire between accelerator
control and adjuster and ASM. After repairs, perform
DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
6) Using DVOM, measure resistance between ASM connector
terminals No. 26 (Gray wire) and No. 28 (Black/White wire). If
resistance is infinite, go to step 8). If resistance is not infinite,
go to next step.
7) Repair short to ground in Gray wire between accelerator
control and adjuster and ASM. After repairs, go to step 19).
8) Using DVOM, measure resistance between ASM harness
connector terminal No. 22 (White wire) and accelerator adjuster
connector terminal “A”. If resistance is 0-5 ohms, go to step 10). If
resistance is not 0-5 ohms, go to next step.
9) Repair open circuit in White wire between accelerator
control and adjuster and ASM. After repairs, perform
DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
10) Using DVOM, measure resistance between ASM connector
terminal No. 49 (White wire) and accelerator adjuster connector
terminal “A”. If resistance is 0-5 ohms, go to next step. If
resistance is not 0-5 ohms, go to step 9).
11) Using DVOM, measure resistance between ASM connector
terminal No. 26 (Gray wire) and accelerator adjuster connector
terminal “B”. If resistance is 0-5 ohms, go to step 13). If resistance
is not 0-5 ohms, go to next step.
12) Repair open circuit in Gray wire between accelerator
control and adjuster and ASM. After repairs, go to step 19).
13) Using DVOM, measure resistance between ASM connector
terminal No. 53 (Gray wire) and accelerator adjuster connector
terminal “B”. If resistance is 0-5 ohms, go to next step. If
resistance is not 0-5 ohms, go to step 12).
14) Turn ignition on, engine off. Using DVOM, measure voltage
at ASM connector terminal No. 22 (White wire). If voltage is more than
one volt, go to next step. If voltage is not more than one volt, go to
step 16).
15) Repair short to voltage in White wire between accelerator
control and adjuster and ASM. After repairs, go to step 19).
16) Using DVOM, measure voltage at ASM connector terminal No.
26 (Gray wire). If voltage is more than one volt, go to next step. If
voltage is not more than one volt, go to step 18).
17) Repair short to voltage in Gray wire between accelerator
control and adjuster and ASM. After repairs, go to step 19).
18) Replace ASM. See
ACCELERATOR & SERVO CONTROL MODULE (CAMARO & FIREBIRD) under REMOVAL &
INSTALLATION. After repairs, go to next step.
19) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0182: THROTTLE REDUCTION MOTOR CIRCUIT RANGE/PERFORMANCE
(CAMARO & FIREBIRD)
Circuit Description
Throttle position signal is used by Accelerator & Servo
Module (ASM) to control actual throttle position that is requested by
EBCM. EBCM compares delivered throttle position sensor value that is
sent from ASM to throttle position sensor value sent from PCM over
Class 2 serial data line.
DTC sets if ASM delivers current greater than 18 amps to
accelerator control and adjuster for more than three seconds without
cable adjuster reaching its desired position.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Inspect accelerator control and adjuster cables/linkages
for any problems that could cause binding or sticking. If any problems
are found, go to next step. If no problems are found, go to step 4).
3) Repair as necessary. After repairs, go to step 7).
4) Check to see if DTC C0181 is also set as a current DTC. If
DTC is also set, see DTC C0181: THROTTLE REDUCTION MOTOR CIRCUIT
MALFUNCTION (CAMARO & FIREBIRD). If DTC is not set, go to next step.
5) Install scan tool and clear DTCs. Raise rear of vehicle so
that rear wheels are at least 6 inches off of floor. Start engine.
Using scan tool in TCS DATA LIST, monitor THROTTLE ANGLE. Depress
brake pedal, put vehicle in gear, then release brake pedal. Depress
and hold accelerator pedal between 15 degrees and 45 degrees for at
least 4 seconds. If DTC resets, go to next step. If DTC does not
reset, perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
6) Replace accelerator control and adjuster assembly. See
ADJUSTER ASSEMBLY (CAMARO & FIREBIRD) under REMOVAL & INSTALLATION.
After repairs, go to next step.
7) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
If an intermittent malfunction exists, see
INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.

DTC C0186: LATERAL ACCELEROMETER MALFUNCTION (INTRIGUE)
Circuit Description
Vehicle Stability Enhancement System (VSES) uses lateral
accelerometer input when calculating desired yaw rate. Usable output
voltage range for lateral accelerometer is 0.25-4.75 volts. Lateral
accelerometer sensor bias compensates for sensor mounting alignment
errors and electronic signal errors.
DTC sets when voltage at lateral accelerometer signal output
to EBCM falls outside 0.25-4.75 volts for more than 100 milliseconds.
Vehicle speed must be greater than 25 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM. Install Universal
Pinout Box (J 39700) with Cable Adapter (J 39700-530) between EBCM and
EBCM connector. Turn ignition on, engine off. Using DVOM, measure
voltage between universal pinout box terminals No. 10 (Light Blue
wire) and No. 15 (Black/White wire). If voltage is 0.25-4.75 volts,
see DIAGNOSTIC AIDS. If voltage is not 0.25-4.75 volts, go to next
step.
3) Turn ignition off. Disconnect yaw/lateral accelerometer
sensor. Turn ignition on, engine off. Using DVOM, measure voltage
between ignition (Pink wire) and ground (Gray/Black wire) circuits of
yaw/lateral accelerometer sensor. If battery voltage is present, go to
step 5). If battery voltage is not present, go to next step.
4) Check Pink wire between yaw/lateral accelerometer sensor
and underhood accessory wiring junction block for high resistance or
open. If problem was found, repair as necessary. After repairs, go to
step 19). If problem was not found, see POWER DISTRIBUTION article in
WIRING DIAGRAMS.
5) Reconnect yaw/lateral accelerometer sensor. Using DVOM,
measure voltage between universal pinout box terminals No. 10 (Light
Blue wire) and No. 15 (Black/White wire). If voltage is less than 4.75
volts, go to next step. If voltage is not less than 4.75 volts, go to
step 13).
6) Using DVOM, measure voltage between universal pinout box
terminals No. 10 (Light Blue wire) and No. 15 (Black/White wire). If
voltage is greater than 0.25 volt, go to next step. If voltage is not
greater than 0.25 volt, go to step 12).
7) Using DVOM, measure voltage between universal pinout box
terminals No. 16 (Orange wire) and No. 15 (Black/White wire). If
voltage is less than 2 volts, go to step 11). If voltage is not less
than 2 volts, go to next step.
8) Using DVOM, measure voltage between universal pinout box
terminals No. 16 (Orange wire) and No. 15 (Black/White wire). If
voltage is greater than 3 volts, go to step 10). If voltage is not
greater than 3 volts, go to next step.
9) Turn ignition off. Disconnect negative battery cable.
Measure resistance between Gray/Black wire of yaw/lateral
accelerometer connector and ground. If resistance is 0-5 ohms, go to
step 16). If resistance is not 0-5 ohms, go to step 14).
10) Check Orange wire (5-volt reference circuit) of
yaw/lateral accelerometer sensor for short to voltage. If problem was
found, repair as necessary. After repairs, go to step 19). If problem
was not found, go to step 15).
11) Check Orange wire (5-volt reference circuit) of
yaw/lateral accelerometer sensor for short to ground, high resistance
or open. If problem was found, repair as necessary. After repairs, go
to step 19). If problem was not found, go to next step.
12) Check Light Blue wire (lateral accelerometer signal
circuit) of yaw/lateral accelerometer sensor for short to ground, high
resistance or open. If problem was found, repair as necessary. After
repairs, go to step 19). If problem was not found, go to step 15).
13) Check Light Blue wire (lateral accelerometer signal
circuit) of yaw/lateral accelerometer sensor for short to voltage. If
problem was found, repair as necessary. After repairs, go to step 19).
If problem was not found, go to step 15).
14) Disconnect EBCM. Check Gray/Black wire (ground circuit)
of yaw/lateral accelerometer sensor for high resistance or open. If
problem was found, repair as necessary. After repairs, go to step 19).
If problem was not found, go to next step.
15) Check yaw/lateral accelerometer sensor connector for poor
connections. If problem was found, repair as necessary. After repairs,
go to step 19). If problem was not found, go to step 17).
16) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 19). If problem
was not found, go to step 18).
17) Replace yaw/lateral accelerometer sensor. See
YAW/LATERAL ACCELEROMETER SENSOR (INTRIGUE) under REMOVAL &
INSTALLATION. After repairs, go to step 19).
18) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
19) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0187: LATERAL ACCELEROMETER CIRCUIT RANGE/PERFORMANCE
(INTRIGUE)
Circuit Description
Vehicle Stability Enhancement System (VSES) uses lateral
accelerometer input when calculating desired yaw rate. Usable output
voltage range for lateral accelerometer 0.25-4.75 volts. Scan tool
will report zero lateral acceleration as 2.5 volts with no sensor bias
present. Lateral accelerometer sensor bias compensates for sensor
mounting alignment errors and electronic signal errors.
DTC sets when one of the following exists:
* A reference lateral acceleration from data of yaw rate
sensor, wheel speed sensors, and steering angle sensor
is used to test lateral accelerometer signal. If during
stable driving conditions, lateral accelerometer signal
becomes larger than 0.26 g, EBCM controller will disregard
signal so that a false EBCM intervention is prevented.
A malfunction is detected if this condition continues
for more than two seconds.
* Under normal driving conditions, long time filtered
driving direction is straight ahead. Long time filtered
lateral accelerometer value is called offset. If offset
value is higher than 0.23 g, a malfunction is detected.
Malfunction time depends on driving distance, vehicle
speed and the amount of malfunctioning lateral accelerometer
signal.
* Lateral accelerometer signal is limited to an electrical
stop of 1.8 g. If lateral accelerometer signal is greater
than 1.5 g for more than 500 milliseconds, a malfunction
is detected.
* At a standstill, range of lateral accelerometer signal
is less than 0.7 g. If lateral accelerometer signal
is greater than 0.7 g at standstill, a malfunction
is detected.
* Lateral accelerometer signal cannot change rapidly
under normal driving conditions. If lateral accelerometer
signal is changing faster than 55 g per second, a malfunction
is detected.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Perform STEERING ANGLE SENSOR CENTERING procedure under
PROGRAMMING. If centering procedure was completed successfully, go to
next step. If centering procedure was not completed successfully, go
to step 7).
3) Turn ignition off. Disconnect EBCM connector. Install
Universal Pinout Box (J 39700) with Cable Adapter (J 39700-530)
between EBCM and EBCM connector. Turn ignition on, engine off. Using
DVOM, measure voltage between universal pinout box terminals No. 10
(Light Blue wire) and No. 15 (Black/White wire). If voltage is 2.3-2.7
volts, go to next step. If voltage is not 2.3-2.7 volts, go to step
8).
4) Using DVOM, measure voltage between universal pinout box
terminals No. 26 (Dark Blue wire) and No. 15 (Black/White wire). If
voltage is 2.3-2.7 volts, go to next step. If voltage is not 2.3-2.7
volts, go to step 8).
5) Using scan tool, clear DTCs. Perform DIAGNOSTIC TEST
DRIVE. If DTC resets, go to next step. If DTC does not reset, see
DIAGNOSTIC AIDS.
6) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to step 9).
7) Replace steering angle sensor. See appropriate STEERING
COLUMNS article in STEERING. After repairs, go to step 9).
8) Replace yaw/lateral accelerometer sensor. See
YAW/LATERAL ACCELEROMETER SENSOR (INTRIGUE) under REMOVAL &
INSTALLATION. After repairs, go to next step.
9) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Find out from customer under what condition DTC was set. This
information will help to duplicate failure. Check vehicle for proper
alignment. Car should not pull in either direction while driving
straight on a level surface. During diagnosis, park vehicle on a level
surface. Check for malfunctioning EBCM and lateral accelerometer.
Snapshot function on scan tool can help find an intermittent DTC.
Diagnostic Test Drive
When servicing vehicles with Vehicle Stability Enhancement
System (VSES), test drives will be necessary to allow all tests to be
run, and all system functions to be enabled and exercised. A test
drive may also be required to duplicate specific DTCs covered in this
section. Diagnostic system check (including test drive) should be run
when vehicle repairs are complete in order to verify repair.
Diagnostic test drive will vary for ABS/TCS or VSES problems. The
following is a suggested VSES diagnostic test drive.
1) Read diagnostic aids and circuit description.
2) Reconnect any previously disconnected components.
3) Start engine.
4) Drive vehicle under following conditions for at least 10
minutes.
* Highway driving.
* Rough roads.
* Perform turning maneuvers (curved freeway entrance
ramp, parking lot maneuvers) and high steering angles
and yaw rates at low speeds.
* Verify customers concern and duplicate driving conditions.
* With engine still running, use scan tool and check
for any DTCs.

DTC C0196: YAW RATE CIRCUIT MALFUNCTION (INTRIGUE)
Circuit Description
Vehicle Stability Enhancement System (VSES) is activated by
EBCM calculating desired yaw rate and comparing it to actual yaw rate
input. Desired yaw rate is calculated from measured steering wheel
position, vehicle speed, and lateral acceleration. Difference between
desired yaw rate and actual yaw rate is yaw rate error, which is a
measurement of oversteer or understeer. If yaw rate error becomes too
large, EBCM will attempt to correct vehicle’s yaw motion by applying
differential braking to wheels. To correct for oversteer, differential
braking is used on left front or right front wheel brake. To correct
for understeer, differential braking is used on left rear or right
rear wheel brake.
DTC sets when yaw rate sensor signal input voltage is less
than 0.23 volt or greater than 4.78 volts for more than 100
milliseconds.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM. Install Universal
Pinout Box (J 39700) with Cable Adapter (J 39700-530) between EBCM and
EBCM connector. Turn ignition on, engine off. Using DVOM, measure
voltage between universal pinout box terminals No. 26 (Dark Blue wire)
and No. 15 (Black/White wire). If voltage is 0.23-4.78 volts, see
DIAGNOSTIC AIDS. If voltage is not 0.23-4.78 volts, go to next step.
3) Turn ignition off. Disconnect yaw/lateral accelerometer
sensor. Turn ignition on, engine off. Using DVOM, measure voltage
between ignition (Pink wire) and ground (Gray/Black wire) circuits of
yaw/lateral accelerometer sensor. If battery voltage is present, go to
step 5). If battery voltage is not present, go to next step.
4) Check Pink wire between yaw/lateral accelerometer sensor
and underhood accessory wiring junction block for high resistance or
open. If problem was found, repair as necessary. After repairs, go to
step 19). If problem was not found, see POWER DISTRIBUTION article in
WIRING DIAGRAMS.
5) Reconnect yaw/lateral accelerometer sensor. Using DVOM,
measure voltage between universal pinout box terminals No. 26 (Dark
Blue wire) and No. 15 (Black/White wire). If voltage is less than 4.78
volts, go to next step. If voltage is not less than 4.78 volts, go to
step 13).
6) Using DVOM, measure voltage between universal pinout box
terminals No. 26 (Dark Blue wire) and No. 15 (Black/White wire). If
voltage is greater than 0.23 volt, go to next step. If voltage is not
greater than 0.23 volt, go to step 12).
7) Using DVOM, measure voltage between universal pinout box
terminals No. 16 (Orange wire) and No. 15 (Black/White wire). If
voltage is less than 2 volts, go to step 11). If voltage is not less
than 2 volts, go to next step.
8) Using DVOM, measure voltage between universal pinout box
terminals No. 16 (Orange wire) and No. 15 (Black/White wire). If
voltage is greater than 3 volts, go to step 10). If voltage is not
greater than 3 volts, go to next step.
9) Turn ignition off. Disconnect negative battery cable.
Measure resistance between Gray/Black wire of yaw/lateral
accelerometer connector and ground. If resistance is 0-5 ohms, go to
step 16). If resistance is not 0-5 ohms, go to step 14).
10) Check Orange wire (5-volt reference circuit) of
yaw/lateral accelerometer sensor for short to voltage. If problem was
found, repair as necessary. After repairs, go to step 19). If problem
was not found, go to step 15).
11) Check Orange wire (5-volt reference circuit) of
yaw/lateral accelerometer sensor for short to ground, high resistance
or open. If problem was found, repair as necessary. After repairs, go
to step 19). If problem was not found, go to next step.
12) Check Dark Blue wire (yaw rate signal circuit) of
yaw/lateral accelerometer sensor for short to ground, high resistance
or open. If problem was found, repair as necessary. After repairs, go
to step 19). If problem was not found, go to step 15).
13) Check Dark Blue wire (yaw rate signal circuit) of
yaw/lateral accelerometer sensor for short to voltage. If problem was
found, repair as necessary. After repairs, go to step 19). If problem
was not found, go to step 15).
14) Disconnect EBCM. Check Gray/Black wire (ground circuit)
of yaw/lateral accelerometer sensor for high resistance or open. If
problem was found, repair as necessary. After repairs, go to step 19).
If problem was not found, go to next step.
15) Check yaw/lateral accelerometer sensor connector for poor
connections. If problem was found, repair as necessary. After repairs,
go to step 19). If problem was not found, go to step 17).
16) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 19). If problem
was not found, go to step 18).
17) Replace yaw/lateral accelerometer sensor. See
YAW/LATERAL ACCELEROMETER SENSOR (INTRIGUE) under REMOVAL &
INSTALLATION. After repairs, go to step 19).
18) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
19) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Following conditions may cause a malfunction:
* Open in yaw rate signal circuit.
* Short to ground in yaw rate signal circuit.
* Short to voltage in yaw rate signal circuit.
* Open in yaw rate ground circuit.
* Open in ignition voltage circuit.
* Malfunctioning vehicle yaw/lateral accelerometer sensor.
* Malfunctioning EBCM.

DTC C0197: YAW RATE CIRCUIT RANGE/PERFORMANCE (INTRIGUE)
Circuit Description
EBCM triggers a yaw rate sensor test every 40 milliseconds
and switches sensor into test mode. EBCM sends a test signal to sensor
via test circuit. When test is run, measured yaw rate from sensor to
EBCM must be 18-32 degrees per second. At standstill, the vehicle yaw
rate is zero. Yaw rate signal at standstill is called offset. If
calibration at standstill is not possible, a quick calibration during
driving is done. Measured yaw rate is calibrated to a calculated
reference yaw rate signal. Yaw rate sensor sensitivity is estimated by
comparison of reference yaw rate and measured yaw rate during
cornering. Steering angle centering is process by which EBCM
calibrates steering sensor output so output reads zero when steering
wheel is centered. PCS steering angle sensor centering process is
performed manually.
DTC sets if one or more of the following conditions exist:
* Yaw rate sensor signal is out of range for 220-420
milliseconds.
* Yaw rate sensor signal at standstill, which is called offset,
is outside allowed range of -8 to 8 degrees per second.
* Sensor sensitivity, which is estimated by comparing
reference yaw rate and measured yaw rate during cornering,
is outside a predetermined range.
* Yaw rate is changing at a rate greater than 6-23 degrees
per second in 40 milliseconds.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Perform STEERING ANGLE SENSOR CENTERING procedure under
PROGRAMMING. If centering procedure was completed successfully, go to
next step. If centering procedure was not completed successfully, go
to step 7).
3) Turn ignition off. Disconnect EBCM connector. Install
Universal Pinout Box (J 39700) with Cable Adapter (J 39700-530)
between EBCM and EBCM connector. Turn ignition on, engine off. Using
DVOM, measure voltage between universal pinout box terminals No. 10
and No. 15 (Black/White wire). If voltage is 2.3-2.7 volts, go to next
step. If voltage is not 2.3-2.7 volts, go to step 8).
4) Using DVOM, measure voltage between universal pinout box
terminals No. 26 (Dark Blue wire) and No. 15 (Black/White wire). If
voltage is 2.3-2.7 volts, go to next step. If voltage is not 2.3-2.7
volts, go to step 8).
5) Using scan tool, clear DTCs. Perform DIAGNOSTIC TEST DRIVE
under DTC C0187: LATERAL ACCELEROMETER CIRCUIT RANGE/PERFORMANCE
(INTRIGUE). If DTC resets, go to next step. If DTC does not reset, see
DIAGNOSTIC AIDS.
6) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to step 9).
7) Replace steering angle sensor. See appropriate STEERING
COLUMNS article in STEERING. After repairs, go to step 9).
8) Replace yaw/lateral accelerometer sensor. See
YAW/LATERAL ACCELEROMETER SENSOR (INTRIGUE) under REMOVAL &
INSTALLATION. After repairs, go to next step.
9) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Possible causes are a malfunctioning lateral accelerometer or
a malfunctioning EBCM.

DTC C0235-C0237 & P1504: TCS RPM SIGNAL CIRCUIT MALFUNCTION
Circuit Description
RPM signal circuit provides EBCM with an indication of engine
RPM to help determine TCS control methods and rates when a TCS event
takes place.
DTC sets when EBCM does not receive an RPM input signal after
one second, after engine has been started.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Start engine. Vary engine RPM with throttle while
observing tachometer on instrument cluster. If tachometer operates
properly as engine RPM changes, go to next step. If tachometer does
not operate properly as engine RPM changes, go to step 9).
3) Turn ignition off. Disconnect Powertrain Control Module
(PCM) connector C2. Disconnect EBCM connector. Install Universal
Pinout Box (J 39700) using Cable Adapter (J 39700-530) to EBCM harness
connector only. Using DVOM, measure resistance between PCM connector
C2 terminal No. 8 (White wire) on Camaro and Firebird 3.8L, Grand Prix
and Intrigue, or terminal No. 10 on Camaro and Firebird 5.7L, and
universal pinout box terminal No. 11 (White wire) on Camaro, Firebird
and Grand Prix, or terminal No. 7 (White wire) on Intrigue. If
resistance is 0-5 ohms, go to next step. If resistance is not 0-5
ohms, go to step 10).
4) Using DVOM, measure resistance between universal pinout
box terminals No. 11 (White wire) on Camaro, Firebird and Grand Prix
or terminal No. 7 (White wire) on Intrigue and No. 15 (Black wire on
Camaro and Firebird, or Black/White wire on Grand Prix and Intrigue).
If resistance is infinite, go to next step. If resistance is not
infinite, go to step 11).
5) Turn ignition on. Using DVOM, measure voltage between
universal pinout box terminals No. 11 (White wire) on Camaro, Firebird
and Grand Prix, or terminal No. 7 (White wire) on Intrigue, and No. 15
(Black/White wire). If voltage is 0-2 volts, go to next step. If
voltage is not 0-2 volts, go to step 12).
6) Check PCM connector C2 and EBCM connector for damage, poor
terminal contact and corrosion. If connectors are faulty, go to step
13). If connectors are okay, go to next step.
7) Reconnect all connectors. Using scan tool, clear DTCs.
Remove scan tool. Start engine. If DTC resets, go to next step. If DTC
does not reset, perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS &
TESTING.
8) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to step 14).
9) Diagnose PCM. See appropriate SELF-DIAGNOSTICS article in
ENGINE PERFORMANCE. After repairs, go to step 14).
10) Repair open in White wire between PCM and EBCM. After
repairs, go to step 14).
11) Repair short to ground in White wire between PCM and
EBCM. After repairs, go to step 14).
12) Repair short to voltage in White wire between PCM and
EBCM. After repairs, go to step 14).
13) Replace all damaged or corroded terminals and connectors,
or any terminals and connectors with poor terminal contact. After
repairs, go to next step.
14) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0238: TCS THROTTLE POSITION SENSOR COMPARISON
MALFUNCTION (CAMARO & FIREBIRD)
Circuit Description
Throttle position signal is used by Accelerator and Servo
control Module (ASM) to control actual throttle position requested by
EBCM. EBCM compares delivered throttle position sensor value that is
sent from ASM to throttle position sensor value sent from PCM over
Class 2 serial data line.
DTC sets when EBCM detects a difference between PCM throttle
position and throttle position sent from ASM.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Check to see if any PCM Throttle Position Sensor (TPS)
DTCs are set. If DTCs are set, see appropriate SELF-DIAGNOSTICS
article in ENGINE PERFORMANCE.
3) Install scan tool and clear DTCs. Turn ignition off.
Disconnect scan tool. Turn ignition on, with engine off. If DTC
resets, go to next step. If DTC does not reset, perform
DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
4) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
5) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent malfunction may be caused by a poor connection, rubbedthrough
wire insulation, or a broken wire inside insulation.

DTC C0239: TCS SPARK RETARD MONITORING MALFUNCTION (CAMARO &
FIREBIRD)
Circuit Description
Spark Retard is simultaneously controlled by EBCM and PCM.
PCM supplies a 12-volt pull-up voltage. This voltage is monitored by
PCM, EBCM requests spark retard by pulling voltage low.
DTC sets when EBCM senses short to ground, short to battery
voltage or open in Gray/White wire between PCM and EBCM.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM connector. Install
Universal Pinout Box (J 39700) using Cable Adapter (J 39700-25) to
EBCM harness connector only. Turn ignition on, engine off. Using DVOM,
measure voltage between universal pinout box terminal No. 19
(Gray/Black wire) and ground. If voltage is greater than 10 volts, go
to next step. If voltage is not greater than 10 volts, go to step 6).
3) Turn ignition off. Disconnect PCM connector C2. Turn
ignition on, engine off. Using DVOM, measure voltage between universal
pinout box terminal No. 19 (Gray/Black wire) and ground. If voltage is
greater than one volt, go to next step. If voltage is less than one
volt, go to step 5).
4) Repair short to voltage in Gray/Black wire between PCM and
EBCM. After repairs, go to step 11).
5) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to step 11).
6) Turn ignition off. Disconnect PCM connector C2. Using
DVOM, measure resistance between universal pinout box terminals No. 15
(Black wire) and No. 19 (Gray/Black wire). If resistance is infinite,
go to step 8). If resistance is not infinite, go to next step.
7) Repair short to ground in Gray/White wire between PCM and
EBCM. After repairs, go to step 11).
8) Using DVOM, measure resistance between universal pinout
box terminal No. 19 (Gray/Black wire) and PCM connector C2 terminal
No. 53. If resistance is 0-5 ohms, go to step 10). If resistance is
not 0-5 ohms, go to next step.
9) Repair open in Gray/White wire between PCM and EBCM. After
repairs, go to step 11).
10) Diagnose PCM. See appropriate SELF-DIAGNOSTICS article in
ENGINE PERFORMANCE. After repairs, go to next step.
11) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0240: PCM TRACTION CONTROL NOT ALLOWED
Circuit Description
PCM monitors various parameters and will not allow traction
control operation if any parameter falls below a specified value.
DTC sets when PCM detects a malfunction and then causes TCS
shut down until malfunction has been corrected.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition on, engine off. Using scan tool, read any
ABS/TCS DTCs. If any DTCs are set, go to appropriate DTC for
diagnosis. If no other DTCs are set, go to next step.
3) If DTC C0240 is set as a current code, go to step 5). If
DTC C0240 is not set, go to next step.
4) Install scan tool and clear DTC. Remove scan tool.
Carefully drive vehicle at speed greater than 8 MPH for several
minutes. If DTC C0240 is set as a current code, go to next step. If
DTC C0240 is not set, perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS
& TESTING.
5) Perform powertrain OBD system check. See appropriate SELFDIAGNOSTICS
article in ENGINE PERFORMANCE. If vehicle passes OBD
system check, go to next step. If vehicle did not pass OBD system
check, perform tests recommended in self-diagnostics article.
6) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
This code is primarily for information only. As an aid to
technician, if DTC C0240 is a history code, this indicates that there
are no problems in ABS/TCS system. If DTC C0240 is a current code, PCM
has detected a malfunction that would not allow traction control to
function, or there may be a suspect PCM.

DTC C0241 OR P1571: PCM INDICATED REQUESTED TORQUE
MALFUNCTION
Circuit Description
EBCM and PCM simultaneously control traction control. EBCM
sends a requested torque message via a Pulse Width Modulated (PWM)
signal to PCM. Duty cycle of signal is used to determine how much
engine torque EBCM is requesting PCM to deliver. Normal values are 10-
90 percent duty cycle. Signal should be at 90 percent when traction
control is not active and at lower values during traction control
activations. PCM supplies pull up voltage that EBCM switches to ground
to create signal.
If a defective requested torque signal is detected by PCM, a
message is broadcasted back to EBCM via class 2 data line. DTC sets
anytime ignition voltage is present and PCM detects requested torque
PWM signal is less than 5 percent duty cycle or greater than 95
percent duty cycle or requested torque PWM signal is not present for
10 seconds.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Check Powertrain Control Module (PCM) and EBCM grounds for
damaged, loose or corroded connections. See GROUND DISTRIBUTION
article in WIRING DIAGRAMS. If problem was found, repair as necessary.
After repairs, go to step 13). If problem was not found, go to next
step.
3) Install scan tool. Start engine. Using scan tool, observe
TORQUE REQUEST SIGNAL parameter in POWERTRAIN CONTROL MODULE data
list. If scan tool displays less than 100%, see
INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING. If scan
tool does not display less than 100%, go to next step.
4) Turn ignition off. Disconnect EBCM harness connector.
Install Universal Breakout Box (J 39700) using (J 39700-530) Cable
Adapter to EBCM harness connector and EBCM connector. Start engine.
Measure DC duty cycle between universal pinout box terminal No. 27
(Orange wire) and ground. If duty cycle is 5-95 percent, go to next
step. If duty cycle is not 5-95 percent, go to step 6).
5) Measure DC Hz between universal pinout box terminal No. 27
(Orange wire) and ground. If frequency is 121-134 hertz, go to step
8). If frequency is not 121-134, go to next step.
NOTE: Disconnecting EBCM connector and turning ignition on could
cause other modules to set loss of communication DTCs
(Uxxxx). Once EBCM is reconnected, EBCM may set DTC C0241.
6) Turn ignition off. Disconnect cable adapter from EBCM.
Turn ignition on, engine off. Measure voltage between universal pinout
box terminal No. 27 (Orange wire) and ground. If voltage is 4-6 volts,
go to step 10). If voltage is not 4-6 volts, go to next step.
7) Turn ignition off. Disconnect PCM connector. Check Orange
wire between EBCM and PCM for short to voltage or short to ground. If
problem was found, repair as necessary. After repairs, go to step 13).
If problem was not found, go to step10).
8) Turn ignition off. Disconnect PCM harness connector. Check
Orange wire between EBCM and PCM for open or high resistance. If
problem was found, repair as necessary. After repairs, go to step 13).
If problem was not found, go to next step.
9) Check PCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 13). If problem
was not found, go to step 11).
10) Check EBCM connector for poor connections. If problem is
found, repair as necessary. If problem is not found, go to step 12).
11) Replace PCM. See appropriate SELF-DIAGNOSTICS article in
ENGINE PERFORMANCE. After repairs, go to step 13).
12) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
13) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
DTC C0244 OR P1689: PWM DELIVERED TORQUE MALFUNCTION
Circuit Description
Traction control is simultaneously controlled by EBCM and
PCM. PCM sends a delivered torque message via a Pulse Width Modulated
(PWM) signal to EBCM confirming delivered torque level for proper
traction control system operation. EBCM supplies pull up voltage.
DTC sets when ignition voltage is present and PWM signal is
out of range or no signal is received for a period of 2 seconds.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Check PCM and EBCM grounds for damaged, loose or corroded
connections. See GROUND DISTRIBUTION article in WIRING DIAGRAMS. If
problem was found, repair as necessary. After repairs, go to step 12).
If problem was not found, go to next step.
3) Install scan tool. Select display DTC function on scan
tool for PCM. If scan tool displays DTC P1571, see
DTC C0241 OR P1571: PCM INDICATED REQUESTED TORQUE MALFUNCTION. If
scan tool does not display DTC P1571, go to next step.
4) Start engine. Using scan tool, observe PCM-to-EBCM
DELIVERED parameter in PCM data list. If scan tool displays 90
percent, go to next step. If scan tool does not display 90 percent,
see INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.
5) Turn ignition off. Disconnect PCM connector C2. Disconnect
EBCM connector. Install Universal Pinout Box (J 39700) using Cable
Adapter (J 39700-25) to EBCM harness connector and EBCM. Turn ignition
on, with engine off. Using DVOM, measure voltage between universal
pinout box terminals No. 9 (Tan/Black wire) and No. 15 (Black wire for
Camaro and Firebird, or Black/White wire for Grand Prix and Intrigue).
If voltage is equal to battery voltage, go to next step. If voltage is
not equal to battery voltage, go to step 7).
6) Turn ignition off. Disconnect cable adapter from EBCM.
Turn ignition on, engine off. Check delivered torque signal circuit
for short to voltage. If problem was found, repair as necessary. After
repairs, go to step 12). If problem was not found, go to step 8).
7) Turn ignition off. Disconnect cable adapter from EBCM
connector. Check delivered torque signal circuit for open, short to
ground or high resistance. If problem was found, repair as necessary.
After repairs, go to step 12). If problem was not found, go to step
9).
8) Check PCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 12). If problem
was not found, go to step 10).
9) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 12). If problem
was not found, go to step 11).
10) Replace PCM. See appropriate SELF-DIAGNOSTICS article in
ENGINE PERFORMANCE. After repairs, go to step 12).
11) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
12) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.
The following are possible causes of DTC:
* Open in delivered torque circuit.
* Short to ground or voltage in delivered torque circuit.
* Communication frequency problem.
* Communication duty cycle problem.
* Wiring problem, terminal corrosion, or poor connections
in delivered torque circuit.
* EBCM not receiving information from PCM.

DTC C0245: WHEEL SPEED SENSOR FREQUENCY ERROR
Circuit Description
Speed sensor used on this vehicle is a multiple pole magnetic
pickup. This sensor produces an AC signal that EBCM uses frequency
from to calculate wheel speed.
NOTE: Camaro and Firebird use a single rear wheel speed sensor with
3.8L engine.
DTC sets when one of the following occurs:
* EBCM detects a deviation between left and right rear
wheel speeds of greater than 3.75 MPH at a vehicle
speed of less than 62 MPH.
* EBCM detects a deviation between left and right front
wheel speeds of greater than 6.25 MPH at a vehicle
speed of less than 62 MPH.
* EBCM detects a deviation between left and right rear
wheel speeds of greater than 6 percent of vehicle speed
at greater than 62 MPH.
* EBCM detects a deviation between left and right front
wheel speeds of greater than 2.5 MPH plus 6 percent
of vehicle speed at greater than 62 MPH.
This DTC will set when EBCM cannot specifically identify
which wheel speed sensor is causing malfunction. If EBCM can identify
a specific wheel speed sensor causing malfunction, DTC associated with
sensor (DTC C0036, DTC C0041, DTC C0046, or DTC C0051) will be set.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) If DTC C0036, C0041, C0046, C0051 or C0056 is set
concurrently with a history DTC C0245, see
DIAGNOSTIC TROUBLE CODE DEFINITIONS table under DIAGNOSIS & TESTING
for diagnosis. If DTC C0036, C0041, C0046, C0051 or C0056 is not set
concurrently with DTC C0245, go to next step.
3) Check wheel speed sensors and sensor rings for damage. If
sensors or rings are damaged, go to next step. If sensors and rings
are okay, go to step 5).
4) Replace wheel speed sensor or sensor ring. After repairs,
go to step 14).
5) Check wheel speed sensor wiring for physical damage. If
wiring is damaged, go to next step. If wiring is not damaged, go to
step 7).
6) Repair wiring as necessary. After repairs, go to step 14).
7) Check for proper routing of wheel speed sensor wiring
harnesses. Ensure harnesses are routed away from spark plug wires. If
harnesses are properly routed, go to step 9). If harnesses are not
properly routed, go to next step.
8) Reroute wheel speed sensor wiring harnesses away from
spark plug wires. After repairs, go to step 14).
9) Install scan tool. Turn ignition on. Set scan tool to
SNAPSHOT AUTO TRIGGER MODE and monitor wheel speed sensors. Drive
vehicle faster than 8 MPH for several minutes. If scan tool triggers
on any wheel speed sensor, go to next step. If scan tool does not
trigger on any wheel speed sensor, go to step 11).
10) Note which wheel speed sensor triggered scan tool.
Diagnose DTC for sensor that triggered scan tool. After repairs, go to
step 14).
11) Reconnect all previously disconnected components. Using
scan tool, clear DTCs. Remove scan tool. Drive vehicle faster than 8
MPH for several minutes. If DTC resets, go to step 13). If DTC does
not reset, go to next step.
12) Malfunction is intermittent. Inspect all connectors and
wiring harnesses for damage resulting in an open or high resistance
when connected. See INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS &
TESTING. After repairs, go to step 14).
13) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
14) Reconnect all previously disconnected components. Using
scan tool, clear DTCs. Remove scan tool. Drive vehicle faster than 8
MPH for several minutes. If DTC does not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.
If ABS/TCS indicator illuminates only during moist
conditions, inspect wheel speed sensor circuitry for signs of water
intrusion. Clear DTCs and simulate effects of water intrusion using a
saltwater solution. If DTC resets, replace suspect wiring harness.
The following are possible causes of DTC:
* Damaged or missing teeth on one or more wheel speed
sensor rings.
* Large grooves or gouges, or foreign material buildup
in gaps between wheel speed sensor ring teeth.
* Worn front hub bearing assembly, or inner axle bearing
which could allow sensor-to-toothed ring gap to change
excessively.

DTC C0252: ACTIVE BRAKE CONTROL SENSORS UNCORRELATED
(INTRIGUE)
Circuit Description
Vehicle Stability Enhancement System (VSES) is activated by
EBCM calculating desired yaw rate and comparing it to actual yaw rate
input. The desired yaw rate is calculated from measured steering wheel
position, vehicle speed, and lateral acceleration. Difference between
desired yaw rate and actual yaw rate is yaw rate error, which is a
measurement of oversteer or understeer. If yaw rate error becomes too
large, EBCM will attempt to correct vehicle’s yaw motion by applying
differential braking to left or right wheels.
DTC sets when VSES is engaged for 10 seconds with yaw rate
error always in either understeer or oversteer (under this condition,
this DTC will set by itself) or yaw rate error is greater than 10
degrees/second for 5 seconds. Steer angle must have been centered,
VSES is active, direction (understeer or oversteer) of yaw rate error
has not changed and lateral acceleration is less than 0.5 g.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Install scan tool. Turn ignition on,
engine off. Select ABS DTC display function. If scan tool displays any
DTC other than DTC C0252, see DIAGNOSTIC TROUBLE CODE DEFINITIONS
table under DIAGNOSIS & TESTING for diagnosis. If scan tool does not
display any other DTCs, go to next step.
3) Using scan tool, clear DTCs. Perform DIAGNOSTIC TEST
DRIVE. Using scan tool, select ABS DTC display function. If DTC
resets, go to next step. If DTC does not reset, see DIAGNOSTIC AIDS.
4) Using scan tool, select VSES data list. Compare data to
typical values located in VSES SCAN TOOL DATA LIST table. See
VSES SCAN TOOL DATA LIST table. If all parameters are correct, see
INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING. If all
parameters are not correct, go to next step.
5) Check wiring harness connectors for the following: EBCM,
brake pressure sensor, steering angle sensor, yaw/lateral
accelerometer sensor, left front wheel speed sensor, right front wheel
speed sensor, left rear wheel speed sensor and right rear wheel speed
sensor. If problem was found, repair as necessary. After repairs, go
to next step. If problem was not found, see
INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.
6) Reconnect previously disconnected components and
connectors. Using scan tool, clear DTCs. If DTC does not reset, system
is okay.
VSES SCAN TOOL DATA LIST
S__c__a__n__ __T__o__o__l__ __P__a__r__a__m__e__t__e__r__ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __ __U__n__i__t__s__ __ __ __ __ __ __ __ __ __T__y__p__i__c__a__l__ __D__a__t__a__ __V__a__l__u__e_
BPMV Pressure Sensor …………… PSI ……………… Varies
Lateral Acceleration Sensor ……… g …………………… 0
Left Front Wheel Speed …………. MPH ………………….. 0
Left Rear Wheel Speed ………….. MPH ………………….. 0
Right Front Wheel Speed ………… MPH ………………….. 0
Right Rear Wheel Speed …………. MPH ………………….. 0
VSES Active …………………. Yes/No ………………… No
VSES Auto Learn Complete ……… Yes/No ………………… No
VSES Failed …………………. Yes/No ………………… No
VSES Malfunction …………… Set/Not Set …………. Not Set
VSES Steering Angle Sensor …….. Deg. ……………… Varies
Yaw Rate Sensor ……………… Deg./Sec. ………………… 0
___________________________________________________________________________________________________________________________________________
Diagnostic Aids
During diagnosis, park vehicle on a level surface. Check
vehicle for proper alignment. Car should not pull in either direction
while driving straight on a level surface. Find out from customer the
conditions under which DTC was set. This information will help to
duplicate failure. Snapshot function on scan tool can help find an
intermittent DTC.
Diagnostic Test Drive
When servicing vehicles with Vehicle Stability Enhancement
System (VSES), test drives will be necessary to allow all tests to be
run, and all system functions to be enabled and exercised. A test
drive may also be required to duplicate specific DTCs covered in this
section. Diagnostic system check (including test drive) should be run
when vehicle repairs are complete in order to verify repair.
Diagnostic test drive will vary for ABS/TCS or VSES problems. The
following is a suggested VSES diagnostic test drive.
1) Read diagnostic aids and circuit description.
2) Reconnect any previously disconnected components.
3) Start engine.
4) Drive vehicle under following conditions for at least 10
minutes.
* Highway driving.
* Rough roads.
* Perform turning maneuvers (curved freeway entrance
ramp, parking lot maneuvers) and high steering angles
and yaw rates at low speeds.
* Verify customers concern and duplicate driving conditions.
* With engine still running, use scan tool and check
for any DTCs.

DTC C0253: CENTERING FAULT (INTRIGUE)
Circuit Description
Steer angle centering is the process by which EBCM calibrates
steering sensor output so output reads zero when steering wheel is
centered.
DTC sets if steering angle sensor Controller Area Network
(CAN) message or EBCM indicates an uncentered sensor and vehicle speed
is greater than 25 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Install scan tool. Turn ignition on,
engine off. Select ABS DTC display function. If scan tool displays any
DTC other than DTC C0253, see DIAGNOSTIC TROUBLE CODE DEFINITIONS
table under DIAGNOSIS & TESTING for diagnosis. If scan tool does not
display any other DTCs, go to next step.
3) Perform steering angle sensor centering procedure. See
STEERING ANGLE SENSOR CENTERING under PROGRAMMING. If centering
procedure was successfully completed, go to next step. If centering
procedure was not successfully completed, go to step 5).
4) Using scan tool, clear DTCs. Test drive vehicle. See
DIAGNOSTIC TEST DRIVE under DTC C0252: ACTIVE BRAKE CONTROL SENSORS
UNCORRELATED (INTRIGUE). If DTC resets, go to step 6). If DTC does not
reset, see DIAGNOSTIC AIDS.
5) Replace steering angle sensor. See appropriate STEERING
COLUMNS article in STEERING. After repairs, go to step 7).
6) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
7) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Perform steering angle sensor centering procedure. See
STEERING ANGLE SENSOR CENTERING under PROGRAMMING.

DTC C0266: ADS CONTROLLER MALFUNCTION (CAMARO & FIREBIRD)
Circuit Description
This circuit monitors DELIVERED THROTTLE POSITION input for
proper operation.
DTC sets anytime ignition is on and EBCM does not receive a
DELIVERED THROTTLE POSITION input.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect and check Accelerator and
Servo control Module (ASM) and connector for corrosion or damage. If
connector is faulty, go to step 7). If connector is okay, go to next
step.
3) Measure resistance between ASM connector terminal No. 28
(Black/White wire) and ground. If resistance is 0-5 ohms, go to next
step. If resistance is not 0-5 ohms, go to step 8).
4) Measure resistance between ASM connector terminal No. 55
(Black/White wire) and ground. If resistance is 0-5 ohms, go to next
step. If resistance is not 0-5 ohms, go to step 8).
5) Turn ignition on, engine off. Using DVOM, measure voltage
between ASM harness connector terminals No. 1 (Pink wire) and No. 28
(Black/White wire). If voltage is equal to battery voltage, go to step
10). If voltage is not equal to battery voltage, go to next step.
6) Repair open or high resistance in Pink wire between ASM
and engine wiring harness junction block 2. After repairs, go to step
16).
7) Repair ASM connector as necessary. After repairs, go to
step 16).
8) Repair open or high resistance in Black/White wire between
ASM and ground. After repairs, go to step 16).
9) Replace ASM. See
ACCELERATOR & SERVO CONTROL MODULE (CAMARO & FIREBIRD) under REMOVAL &
INSTALLATION. After repairs, go to step 16).
10) Turn ignition off. Disconnect EBCM connector. Install
Universal Pinout Box (J 39700) using Cable Adapter (J 39700-25) to
EBCM harness connector only. Measure resistance between terminals No.
9 (Tan/Black wire) and No. 15 (Black wire). If resistance is infinite,
go to step 12). If resistance is not infinite, go to next step.
11) Repair short to ground in Tan/Black wire between ASM and
EBCM. After repairs, go to step 16).
12) Measure resistance between universal pinout box terminal
No. 9 (Tan/Black wire) and ASM connector terminal No. 35 (Tan/Black
wire). If resistance is 0-5 ohms, go to step 14). If resistance is not
0-5 ohms, go to next step.
13) Repair open or high resistance in Tan/Black wire between
ASM and EBCM. After repairs, go to step 16).
14) Turn ignition on, engine off. Using DVOM, measure voltage
at universal pinout box terminal No. 9 (Tan/Black wire). If voltage is
greater than one volt, go to next step. If voltage is not greater than
one volt, go to step 9).
15) Repair short to voltage in Tan/Black wire between ASM and
EBCM. After repairs, go to next step.
16) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0550: ECU MALFUNCTION
Circuit Description
This DTC identifies a malfunction within EBCM
DTC sets when an internal EBCM malfunction exists.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) If any other DTCs than DTC C0550 are set, see
DIAGNOSTIC TROUBLE CODE DEFINITIONS table under DIAGNOSIS & TESTING
for diagnosis. If no other DTCs than DTC C0550 are set, go to next
step.
3) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
4) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.

DTC C0710: STEERING POSITION SIGNAL MALFUNCTION (INTRIGUE)
Circuit Description
Under normal driving conditions, EBCM monitors steering angle
sensor inputs to see if steering wheel is moving. If steering wheel is
not moving for a set period of time, EBCM assumes vehicle is going in
a straight line. At this point, EBCM looks at steering angle sensor
inputs and considers degree angle to be zero. This is called offset
value. Steer angle centering is process by which EBCM calibrates
steering sensor output so that output reads zero when steering wheel
is centered.
DTC sets if one or more of following conditions exist and
vehicle speed is greater than 25 MPH.
* Steering angle sensor detects an internal malfunction and
sends a Controller Area Network (CAN) message to EBCM.
* If offset value is higher than 15 degrees, a malfunction is
detected. Malfunction time depends on driving distance,
vehicle speed and amount of malfunctioning steering
angle signal.
* Rapid changes of steering angle sensor signal cannot
occur under normal driving conditions. If signal change
is higher than 2000 degrees per second or steering
angle acceleration is higher than 37500 degrees per
second squared, a malfunction is detected.
* A reference steering angle signal based on a vehicle
model is used to check actual steering angle. If measured
steering angle varies from reference steering angle
by more than a predetermined value, a malfunction is
detected.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Install scan tool. Turn ignition on,
engine off. Select ABS DTC display function. If scan tool displays any
DTC other than DTC C0710, see DIAGNOSTIC TROUBLE CODE DEFINITIONS
table under DIAGNOSIS & TESTING for diagnosis. If scan tool does not
display any other DTC, go to next step.
3) Perform steering angle sensor centering procedure. See
STEERING ANGLE SENSOR CENTERING under PROGRAMMING. If centering
procedure was successfully completed, go to next step. If centering
procedure was not successfully completed, go to step 5).
4) Using scan tool, clear DTCs. Test drive vehicle. See
DIAGNOSTIC TEST DRIVE under DTC C0252: ACTIVE BRAKE CONTROL SENSORS
UNCORRELATED (INTRIGUE). If DTC resets, go to step 6). If DTC does not
reset, see DIAGNOSTIC AIDS.
5) Replace steering angle sensor. See appropriate STEERING
COLUMNS article in STEERING. After repairs, go to step 7).
6) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
7) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Perform steering angle sensor centering procedure. See
STEERING ANGLE SENSOR CENTERING under PROGRAMMING.

DTC C0870: BPMV PRESSURE SENSOR REFERENCE CIRCUIT MALFUNCTION
(INTRIGUE)
Circuit Description
Brake pressure sensor reference voltage is monitored for an
over or under voltage condition.
DTC sets when 5-volt reference is greater than 5.6 volts or
less than 4.4 volts for more than 60 milliseconds.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM. Install Universal
Pinout Box (J 39700) with Cable Adapter (J 39700-530) between EBCM and
EBCM connector. Turn ignition on, engine off. Using DVOM, measure
voltage between universal pinout box terminals No. 17 (Orange wire)
and No. 15 (Black/White wire). If voltage is 4.4-5.6 volts, see
DIAGNOSTIC AIDS. If voltage is not 4.4-5.6 volts, go to next step.
3) Turn ignition off. Disconnect brake pressure sensor. Turn
ignition on, engine off. Using DVOM, measure voltage between universal
pinout box terminals No. 28 (Gray wire) and No. 15 (Black/White wire).
If voltage is greater than 4.4 volts, go to next step. If voltage is
not greater than 4.4 volts, go to step 5).
4) Using DVOM, measure voltage between universal pinout box
terminals No. 28 (Gray wire) and No. 15 (Black/White wire). If voltage
is less than 5.6 volts, go to step8). If voltage is not less than 5.6
volts, go to step 6).
5) Check Gray wire (5-volt reference circuit) between brake
pressure sensor and EBCM for short to ground. If problem was found,
repair as necessary. After repairs, go to step 12). If problem was not
found, go to step 9).
6) Check Gray wire (5-volt reference circuit) between brake
pressure sensor and EBCM for short to voltage. If problem was found,
repair as necessary. After repairs, go to step 12). If problem was not
found, go to next step.
7) Check Gray/Black wire (ground circuit) between brake
pressure sensor and EBCM for high resistance or open. If problem was
found, repair as necessary. After repairs, go to step 12). If problem
was not found, go to step 9).
8) Check brake pressure sensor connector for poor
connections. If problem was found, repair as necessary. After repairs,
go to step 12). If problem was not found, go to step 10).
9) Check connector of EBCM for poor connections. If problem
was found, repair as necessary. After repairs, go to step 12). If
problem was not found, go to step 11).
10) Replace brake pressure sensor. See
BRAKE PRESSURE SENSOR (INTRIGUE) under REMOVAL & INSTALLATION. After
repairs, go to step 12).
11) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
12) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Possible causes of this DTC are open, short to ground or
short to battery voltage in pressure sensor 5-volt reference circuit.

DTC C0875: YAW/LATERAL ACCELEROMETER SENSOR CIRCUIT
MALFUNCTION (INTRIGUE)
Circuit Description
Yaw rate sensor reference voltage is monitored for an over or
under voltage condition.
DTC is set if supply voltage is greater than 5.6 volts or
less than 4.4 volts for more than 200 milliseconds and vehicle speed
is greater than 25 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM. Install Universal
Pinout Box (J 39700) with Cable Adapter (J 39700-530) between EBCM and
EBCM connector. Turn ignition on, engine off. Using DVOM, measure
voltage between universal pinout box terminals No. 16 (Orange wire)
and No. 15 (Black/White wire). If voltage is 4.4-5.6 volts, see
DIAGNOSTIC AIDS. If voltage is not 4.4-5.6 volts, go to next step.
3) Turn ignition off. Disconnect yaw/lateral accelerometer
sensor. Turn ignition on, engine off. Using DVOM, measure voltage
between universal pinout box terminals No. 16 (Orange wire) and No. 15
(Black/White wire). If voltage greater than 4.5 volts, go to next
step. If voltage is not greater than 4.4 volts, go to step 5).
4) Using DVOM, measure voltage between universal pinout box
terminal No. 16 (Orange wire) and No. 15 (Black/White wire). If
voltage is less than 5.6 volts, go to step 8). If voltage is not less
than 5.6 volts, go to step 6).
5) Check Orange wire (5-volt reference circuit) of
yaw/lateral accelerometer sensor for short to ground. If problem was
found, repair as necessary. After repairs, go to step 12). If problem
was not found, go to step 9).
6) Check Orange wire (5-volt reference circuit) of
yaw/lateral accelerometer sensor for short to voltage. If problem was
found, repair as necessary. After repairs, go to step 12). If problem
was not found, go to next step.
7) Check Gray/Black wire (ground circuit) of yaw/lateral
accelerometer sensor for high resistance or open. If problem was
found, repair as necessary. After repairs, go to step 12). If problem
was not found, go to step 9).
8) Check yaw/lateral accelerometer sensor connector for poor
connections. If problem was found, repair as necessary. After repairs,
go to step 12). If problem was not found, go to step 10).
9) Check connector of EBCM for poor connections. If problem
was found, repair as necessary. After repairs, go to step 12). If
problem was not found, go to step 11).
10) Replace yaw/lateral accelerometer sensor. See under
REMOVAL & INSTALLATION. After repairs, go to step 12).
11) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
12) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Possible causes of this DTC are open, short to ground or
short to battery voltage in yaw rate sensor 5-volt reference circuit.

DTC C0896: DEVICE VOLTAGE RANGE/PERFORMANCE
Circuit Description
EBCM is required to operate within a specified range of
voltage to function properly. During ABS and TCS operation, there are
current requirements that will cause voltage to drop. Because of this,
voltage is monitored out of ABS/TCS control to indicate a good
charging system condition, and also during ABS/TCS control when
voltage may drop significantly. PCM also monitors for high voltage
conditions which could damage EBCM.
DTC sets when EBCM operating voltage at terminal No. 8 (Pink
wire) drops to less than 9.4 volts out of ABS/TCS control, or 8.8
volts during ABS/TCS control, or EBCM operating voltage at terminal
No. 8 increases to greater than 17.4 volts. Condition must exist for
more than 500 milliseconds with vehicle speed above 3.6 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn all accessories off. Start engine. Using scan tool,
select ABS/TCS DATA LIST. Monitor battery voltage while running engine
at about 2000 RPM. If voltage is 0-17.4 volts, go to step 4). If
voltage is not 0-17.4 volts, go to next step.
3) Using DVOM, check actual battery voltage while running
engine at about 2000 RPM. If voltage is 0-17.4 volts, go to next step.
If voltage is not 0-17.4 volts, diagnose charging system. See
appropriate GENERATORS & REGULATORS article in STARTING & CHARGING
SYSTEMS.
4) Continue monitoring battery voltage while running engine
at about 2000 RPM, Using scan tool. If voltage is 0-9.4 volts, go to
step 6). If voltage is not 0-9.4 volts, go to next step.
5) Turn ignition off. Disconnect scan tool. Test drive
vehicle faster than 3 MPH. If DTC C0896 resets, go to step 12). If DTC
C0896 does not reset, perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS
& TESTING.
6) Turn ignition off. Disconnect EBCM connector. Install
Universal Pinout Box (J 39700) using Cable Adapter (J 39700-25) to
EBCM harness connector only. Using DVOM, measure resistance between
universal pinout box terminal No. 15 (Black wire for Camaro and
Firebird or Black/White wire for Grand Prix and Intrigue) and ground.
If resistance is 0-5 ohms, go to step 8). If resistance is not 0-5
ohms, go to next step.
7) Repair open or high resistance in Black wire or
Black/White wire between ground and EBCM. After repairs, go to step
13).
8) Turn ignition on, with engine off. Using DVOM, measure
voltage between universal pinout box terminals No. 15 (Black wire for
Camaro and Firebird, or Black/White wire for Grand Prix and Intrigue)
and No. 8 (Pink wire). If voltage is greater than 9.4 volts, go to
step 11). If voltage is not greater than 9.4 volts, go to next step.
9) Turn ignition off. Remove ABS fuse (10-amp) or ABS IGN
fuse (10-amp) in. Using DVOM, measure resistance of Pink wire between
junction block and EBCM connector terminal No. 8. If resistance is 0-5
ohms, diagnose charging system. See appropriate GENERATORS &
REGULATORS article in STARTING & CHARGING SYSTEMS. If resistance is
not 0-5 ohms, go to step 10).
10) Repair open or high resistance in Pink wire between
junction block and EBCM connector terminal No. 8. After repairs, go to
step 13).
11) Turn ignition off. Reconnect all connectors. Disconnect
scan tool. Test drive vehicle faster than 3 MPH. If DTC C0896 resets,
go to next step. If DTC C0896 does not reset, go to step 13).
12) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
13) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
A thorough inspection of wiring and connectors is important
to prevent misdiagnosis. Check for backed-out terminals, improper
mating, broken locks, improperly formed or damaged terminals, poor
terminal-to-wiring connections, or damaged wiring harness. An
intermittent may be caused by a poor connection, rubbed-through wire
insulation, or a broken wire inside insulation.

DTC C0901: DEVICE NO. 2 VOLTAGE LOW (CAMARO & FIREBIRD)
Circuit Description
This circuit monitors voltage level available to Accelerator
and Servo control Module (ASM). If voltage decreases to less than 7.5
volts, full performance of traction control system cannot be
guaranteed.
DTC sets when ignition is on and ignition voltage is less
than 7.5 volts.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Check charging system for proper operation. See
appropriate GENERATORS & REGULATORS article in STARTING & CHARGING
SYSTEMS. If charging system is okay, go to next step.
3) Turn ignition off. Disconnect and check ASM and connector
for corrosion or damage. If connector is faulty, go to step 7). If
connector is okay, go to next step.
4) Measure resistance between ASM connector terminal No. 28
(Black/White wire) and ground. If resistance is 0-5 ohms, go to next
step. If resistance is not 0-5 ohms, go to step 8).
5) Measure resistance between ASM harness connector terminal
No. 55 (Black/White wire) and ground. If resistance is 0-5 ohms, go to
next step. If resistance is not 0-5 ohms, go to step 8).
6) Turn ignition on, engine off. Using DVOM, measure voltage
between ASM connector terminals No. 1 (Pink wire) and No. 28
(Black/White wire). If voltage is greater than 7.5 volts, go to step
9). If voltage is less than one volt, see appropriate GENERATORS &
REGULATORS article in STARTING & CHARGING SYSTEMS.
7) Repair ASM connector as necessary. After repairs, go to
step 10).
8) Repair open or high resistance in Black/White wire or
Black wire between ASM and ground. After repairs, go to step 10).
9) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
10) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Thoroughly inspect wiring and connectors. Failure to
carefully and fully inspect wiring and connectors can result in
misdiagnosis. Misdiagnosis may cause replacement of parts without
repairing malfunction. Inspect other low voltage conditions. Test
charging system. See appropriate GENERATORS & REGULATORS article in
STARTING & CHARGING SYSTEMS.
Following conditions are other possible causes of low system
voltage:
* Charging system malfunction.
* Excessive parasitic drain.
* Weak battery.
* Faulty system ground.
If an intermittent malfunction exists, see
INTERMITTENTS & POOR CONNECTIONS under DIAGNOSIS & TESTING.

DTC U1650: CHASSIS SYSTEM DEDICATED BUS CONTROLLER
MALFUNCTION (INTRIGUE)
Circuit Description
Controller Area Network (CAN) serial data circuit is a high
speed serial data bus used to communicate information between steering
angle sensor and EBCM. When ignition is on, module and steering angle
sensor begin to transmit data between each other. CAN bus circuit is
monitored continuously after ignition is turned on.
DTC sets when line interruptions are detected by CAN message
monitor and vehicle speed is greater than 25 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect EBCM. Install Universal
Pinout Box (J 39700) with Cable Adapter (J 39700-530) to EBCM
connector only. Disconnect steering angle sensor. Using DVOM, Check
CAN HI (Tan/White wire) and CAN LO (Tan wire) circuits for short to
ground between steering angle sensor and EBCM. If problem was found,
repair as necessary. After repairs, go to step 8). If problem was not
found, go to next step.
3) Using DVOM, check CAN HI and CAN LO circuits between
steering angle sensor and EBCM for being shorted together. If problem
was found, repair as necessary. After repairs, go to step 8). If
problem was not found, go to next step.
4) Perform steering angle sensor centering procedure. See
STEERING ANGLE SENSOR CENTERING under PROGRAMMING. If centering
procedure was successfully completed, go to next step. If centering
procedure was not successfully completed, go to step 6).
5) Using scan tool, clear DTCs. Test drive vehicle. See
DIAGNOSTIC TEST DRIVE under DTC C0252: ACTIVE BRAKE CONTROL SENSORS
UNCORRELATED (INTRIGUE). If DTC U1650 reset, go to step 7). If DTC
U1650 did not reset, go to step 8).
6) Replace steering angle sensor. See appropriate STEERING
COLUMNS article in STEERING. After repairs, go to step 8).
7) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
8) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Possible causes of DTC are CAN HI and CAN LO circuits shorted
together, shorted to ground or shorted to voltage.

DTC U1651: CHASSIS SYSTEM DEDICATED BUS SENSOR MALFUNCTION
(INTRIGUE)
Circuit Description
EBCM monitors received messages from steering angle sensor
for corruption or missing messages.
DTC sets when EBCM receives a corrupt or missing message
after 100 milliseconds and vehicle speed is greater than 25 MPH.
Diagnosis
1) Perform DIAGNOSTIC SYSTEM CHECK under DIAGNOSIS & TESTING.
Go to next step.
2) Turn ignition off. Disconnect steering angle sensor
connector. Using DVOM, check ignition circuit (Pink wire) for open. If
problem was found, repair as necessary. After repairs, go to step 12).
If problem was not found, go to next step.
3) Disconnect EBCM connector. Install Universal Pinout Box (J
39700) with Cable Adapter (J 39700-530) between EBCM and the EBCM
connector. Disconnect steering angle sensor. Using DVOM, check ground
circuit (Gray/Black wire) for open. If problem was found, repair as
necessary. After repairs, go to step 12). If problem was not found, go
to next step.
4) Using DVOM, check CAN HI circuit (Tan/White wire) for
open. If problem was found, repair as necessary. After repairs, go to
step 12). If problem was not found, go to next step.
5) Using DVOM, check CAN LO circuit (Tan wire) for open. If
problem was found, repair as necessary. After repairs, go to step 12).
If problem was not found, go to next step.
6) Check steering angle sensor connector for poor
connections. If problem was found, repair as necessary. After repairs,
go to step 12). If problem was not found, go to next step.
7) Check EBCM connector for poor connections. If problem was
found, repair as necessary. After repairs, go to step 12). If problem
was not found, go to next step.
8) Perform steering angle sensor centering procedure. See
STEERING ANGLE SENSOR CENTERING under PROGRAMMING. If centering
procedure was successfully completed, go to next step. If centering
procedure was not successfully completed, go to step 10).
9) Using scan tool, clear DTCs. Test drive vehicle. See
DIAGNOSTIC TEST DRIVE under DTC C0252: ACTIVE BRAKE CONTROL SENSORS
UNCORRELATED (INTRIGUE). If DTC U1651 reset, go to step 11). If DTC
U1651 did not reset, go to step 12).
10) Replace steering angle sensor. See appropriate STEERING
COLUMNS article in STEERING. After repairs, go to step 12).
11) Replace EBCM. See ELECTRONIC BRAKE CONTROL MODULE under
REMOVAL & INSTALLATION. After repairs, go to next step.
12) Using scan tool, clear DTCs. Operate vehicle. If DTC does
not reset, system is okay.
Diagnostic Aids
Possible causes of this DTC are:
* Open in the CAN HI or CAN LO circuit.
* Open in the ignition circuit.
* Open in the ground circuit.
* Malfunctioning steering angle sensor.
* Malfunctioning EBCM.

©, 2014 Rick Muscoplat

Posted on by Rick Muscoplat


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