Pinpoint Test A: No Communication With The Trailer Brake Control (TBC) Module

WARNING: This page is about a different car, the 2006 Ford Pickup, 2006 Ford F550 Super Duty, 2006 Ford F450 Super Duty, and 2006 Ford Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

CAUTION: Use the flex probe kit for all test connections to prevent damage to the wiring terminals. Do not use standard multimeter probes.

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.
    
    Fig 1: Checking Voltage To TBC Module
    Courtesy of FORD MOTOR CO.
- 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.
  
  Fig 2: Checking Ground Circuit 206 (WH) For Open
  Courtesy of FORD MOTOR CO.
- 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.