GM C0045 code and Service Traction Control light on

Fix a GM C0045 code by cleaning corrosion from an electrical connector

GM has issued a technical service bulletin #PIT5427B to address a GM C0045 code along with several other trouble codes like: C0196, C0186, C0287, C0710, C0050, C0800 U0073, U0074 U0077, U0125, U0126, U0100, U0101, U0121, U0415, U0432, U0121, and U0140 on the vehicles listed below.

2010-17 Chevrolet Equinox
2010-17 GMC Terrain

The TSB covers a check engine light (SES MIL), Service ABS, Service Traction Control, Service AWD, Service Suspension Control, or Service Power Steering Message.

GM has determined that all of these issues can be caused by corrosion in the X411 electrical connector located under the rear of the vehicle. The connector is behind and to the left of the fuel tank.

Open the connector and check for corrosion on the terminals. Clean or replace the corroded terminals as necessary.

If the connector can’t be cleaned, search findpigtails.com to locate a replacement.

In addition to the information in the TSB, you must also check the condition of the wheel speed sensor wiring harness. The code tells which sensor harness to check.

C0045  06 : Left Rear Wheel Speed Sensor Circuit Low Voltage/Open
C0045  08 : Left Rear Wheel Speed Sensor Circuit Performance – Signal Invalid
C0045  0F : Left Rear Wheel Speed Sensor Circuit Signal Erratic
C0045  18 : Left Rear Wheel Speed Sensor Circuit Low Signal Amplitude
C0045  5A : Left Rear Wheel Speed Sensor Circuit Not Plausible

To check the wiring harness, disconnect the connector from the sensor. Check for voltage and ground at each sensor terminal. Key in RUN position.

Left front wheel speed sensor: Light Blue >11-volts   Yellow ground
Right front wheel speed sensor: Dark green >11-volts  Tan ground
Left rear wheel speed sensor: Tan >11-volts  Orange/green ground
Right Rear wheel speed sensor: Brown >11-volts  White ground
If you don’t get those readings, check for open or short to ground between the connector and the EBCM.

If all the connections/wires check out, the problem is most likely located in the short harness connector to the wheel speed sensor.

Clean the connector and clear the C0045 code

Use electrical contact cleaner and a nylon brush to remove corrosion from inside the connector. Apply a thin film of dielectric grease after you’ve cleaned it. Then reconnect and clear the code.

©, 2022 Rick Muscoplat