Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Pinpoint Test A: No Communication With The Trailer Brake Control (TBC) Module
- A1 CHECK THE MISSING CONTROLLER AREA NETWORK (CAN) SOURCE IDENTIFIER PID
- Key in ON position.
- Enter the following diagnostic mode on the scan tool: Missing CAN Source Identifier PID.
- Does the PID indicate a missing module?
Yes : For missing powertrain control module (PCM), REFER to ELECTRONIC ENGINE CONTROLS - GASOLINE ENGINES (gasoline engine) or ELECTRONIC ENGINE CONTROLS - DIESEL ENGINE (diesel engine).
For missing anti-lock brake system (ABS) control module, REFER to VEHICLE DYNAMIC SYSTEMS . For missing instrument cluster, REFER to INSTRUMENT CLUSTER .
No : GO to A2.
- A2 CHECK THE VOLTAGE TO THE TBC MODULE
- Key in OFF position.
- Disconnect: TBC Module C2142a.
- Disconnect: TBC Module C2142b.
- Key in ON position.
- Measure the voltage between TBC module, harness side and ground as follows:
- TBC module C2142a-1, circuit 50 (RD), harness side.
- TBC module C2142b-3, circuit 298 (VT/OG), harness side.
- Are the voltages greater than 10 volts?
Yes : GO to A3.
No : VERIFY CJB fuse 101 (30A) is OK. If OK, REPAIR circuit 50 (RD) for an open.
VERIFY CJB fuse 28 (10A) is OK. If OK, REPAIR circuit 298 (VT/OG) for an open.
CLEAR the DTCs. REPEAT the self-test.
- A3 CHECK GROUND CIRCUIT 206 (WH) FOR AN OPEN
- Key in OFF position.
- Measure the resistance between TBC module C2124a-4, circuit 206 (WH), harness side and ground.
- Is the resistance less than 5 ohms?
Yes : REFER to MODULE COMMUNICATIONS NETWORK to continue diagnosis of the communication network.
No : REPAIR circuit 206 (WH) for an open. CLEAR the DTCs. REPEAT the self-test.
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.