What causes ABS light?

Why is my ABS light on?

What should I do with ABS light on?

The antilock brake system (ABS) consists of wheel

Wheel speed sensor

speed sensors, wiring harness, pump and valves, and computer. The computer constantly checks the condition of the wheel speed sensors, wiring harness and pump and valves. The ABS light on indicates a fault with any of those components, it sets a trouble code, turns off the ABS system, and turns on the ABS light.

Where to start diagnosing an ABS light on?

It ALWAYS starts by getting the trouble code. Without that code, you’re simply shooting blind. People will tell you it’s often a bad wheel speed sensor. But which one? That’s where the trouble code comes in handy. It narrows down the starting point. Trouble codes are arranged by vehicle system. Powertrain trouble codes start with “P”, while Chassis “C” and Body “B” and Digital communications start with “U”. Most inexpensive code readers only read “P” codes. Here are some typical ABS light on trouble codes.

B2747 TRACTION CONTROL SWITCH CIRCUIT LOW

C1214 SYSTEM RELAY CONTACT OR COIL CIRCUIT OPEN

C1216 ELECTRONIC BRAKE CONTROL RELAY COIL CIRCUIT OPEN

C1217 BPMV PUMP MOTOR RELAY CONTACTS CIRCUIT OPEN

C1218 PUMP MOTOR CIRCUIT SHORTED TO VOLTAGE OR MOTOR GROUND OPEN

C1221 LF WHEEL SPEED SENSOR INPUT SIGNAL IS 0;

C1222 RF WHEEL SPEED SENSOR INPUT SIGNAL IS 0;

C1223 LR WHEEL SPEED SENSOR INPUT SIGNAL IS 0;

C1224 RR WHEEL SPEED SENSOR INPUT SIGNAL IS 0;

C1225 LF EXCESSIVE WHEEL SPEED VARIATION;

C1226 RF EXCESSIVE WHEEL SPEED VARIATION;

C1227 LR EXCESSIVE WHEEL SPEED VARIATION;

C1228 RR EXCESSIVE WHEEL SPEED VARIATION;

C1232 LF WHEEL SPEED CIRCUIT OPEN OR SHORTED;

C1233 RF WHEEL SPEED CIRCUIT OPEN OR SHORTED;

C1234 LR WHEEL SPEED CIRCUIT OPEN OR SHORTED;

C1235 RR WHEEL SPEED CIRCUIT OPEN OR SHORTED

C1236 LOW SYSTEM SUPPLY VOLTAGE

C1237 HIGH SYSTEM SUPPLY VOLTAGE

C1238 BRAKE THERMAL MODEL EXCEEDED

C1242 PUMP MOTOR CIRCUIT OPEN;

C1243 BPMV PUMP MOTOR STALLED

C1248 EBCM TURNED THE RED BRAKE WARNING INDICATOR ON

C1254 ABNORMAL SHUTDOWN DETECTED

C1255 EBCM INTERNAL MALFUNCTION;

C1256 EBCM INTERNAL MALFUNCTION

C1261 LF INLET VALVE SOLENOID MALFUNCTION;

C1262 LF OUTLET VALVE SOLENOID MALFUNCTION;

C1263 RF INLET VALVE SOLENOID MALFUNCTION;

C1264 RF OUTLET VALVE SOLENOID MALFUNCTION;

C1265 LR INLET VALVE SOLENOID MALFUNCTION;

C1266 LR OUTLET VALVE SOLENOID MALFUNCTION;

C1267 RR INLET VALVE SOLENOID MALFUNCTION;

C1268 RR OUTLET VALVE SOLENOID MALFUNCTION;

C1271 LF TCS MASTER CYLINDER ISOLATION VALVE MALFUNCTION;

C1272 LF TCS PRIME VALVE MALFUNCTION;

C1273 RF TCS MASTER CYLINDER ISOLATION VALVE MALFUNCTION;

C1274 RF TCS PRIME VALVE MALFUNCTION

C1276 DELIVERED TORQUE SIGNAL CIRCUIT MALFUNCTION;

P1644 DELIVERED TORQUE OUTPUT CIRCUIT;

P1689 TRACTION CONTROL DELIVERED TORQUE CONTROL CIRCUIT

C1277 REQUESTED TORQUE SIGNAL CIRCUIT MALFUNCTION;

P1571 TCS PWM CIRCUIT NO FREQUENCY

C1278 TCS TEMPORARILY INHIBITED BY PCM

C1291 OPEN BRAKE LAMP SWITCH CONTACTS DURING DECELERATION

C1294 BRAKE LAMP SWITCH CIRCUIT ALWAYS ACTIVE

C1295 BRAKE LAMP SWITCH CIRCUIT OPEN

With all those possibilities you can see why it’s SO important to start your diagnosis with the trouble codes.

Will my brakes work when I have an ABS light on?

Yes. Your brakes will continue to work but you will not have the anti-lock function.

Why is my Traction Light OFF warning light on?

The traction control system relies on information from the ABS system. When the ABS system shuts off, your traction control system also shuts down and turns on the Traction Light OFF warning light to alert you that you no longer have active traction control.

©, 2018 Rick Muscoplat