Pinpoint Test D: The Trailer Brake Control (TBC) Module Does Not Respond To The Scan Tool

Communications Network

Pinpoint Test D: The Trailer Brake Control (TBC) Module Does Not Respond To The Scan Tool

Normal Operation

The Trailer Brake Control (TBC) module is optional equipment. The TBC (Trailer Brake Control) module communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).

This pinpoint test is intended to diagnose the following:

- Fuse

- Wiring, terminals or connectors

- TBC (Trailer Brake Control) module

PINPOINT TEST D : THE TBC (Trailer Brake Control) MODULE DOES NOT RESPOND TO THE SCAN TOOL

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings.

D1 CHECK THE TBC (Trailer Brake Control) MODULE POWER SUPPLY CIRCUITS FOR AN OPEN

- Ignition OFF.

- Disconnect: TBC (Trailer Brake Control) Module C2142.

- Ignition ON.

- Measure the voltage between the TBC (Trailer Brake Control) module, harness side and ground as follows:

Connector-Pin Circuit C2142-8 SBB22 (BN/RD) C2142-12 CBP35 (YE/GY)






Are the voltages greater than 10 volts?

Yes
GO to D2.

No
VERIFY the Body Control Module (BCM) fuse 35 (5A) and Battery Junction Box (BJB) fuse 22 (30A) are OK. If OK, REPAIR the circuit in question.
If not OK, REFER to the Wiring Diagrams to identify the possible causes of the circuit short. CLEAR the DTCs. REPEAT the network test with the scan tool. [1][2]Diagrams By Number

D2 CHECK THE TBC (Trailer Brake Control) MODULE GROUND CIRCUIT FOR AN OPEN

- Ignition OFF.

- Disconnect: Negative Battery Cable.

- Measure the resistance between the TBC (Trailer Brake Control) module C2124-11, circuit GD115 (BK/GY), harness side and ground.





Is the resistance less than 5 ohms?

Yes
GO to D3.

No
REPAIR the circuit. CLEAR the DTCs. REPEAT the network test with the scan tool.

D3 CHECK THE HS-CAN (High Speed Controller Area Network) CIRCUITS BETWEEN THE TBC (Trailer Brake Control) MODULE AND THE DLC (Data Link Connector) FOR AN OPEN

- Measure the resistance between the TBC (Trailer Brake Control) module C2142-2, circuit VDB04 (WH/BU), harness side and the Data Link Connector (DLC) C251-6, circuit VDB04 (WH/BU), harness side.





- Measure the resistance between the TBC (Trailer Brake Control) module C2142-3, circuit VDB05 (WH), harness side and the DLC (Data Link Connector) C251-14, circuit VDB05 (WH), harness side.





Are the resistances less than 5 ohms?

Yes
CONNECT the negative battery cable. GO to D4.

No
REPAIR the circuit in question. REPEAT the network test with the scan tool.

D4 CHECK FOR CORRECT TBC (Trailer Brake Control) MODULE OPERATION

- Disconnect all the TBC (Trailer Brake Control) module connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the TBC (Trailer Brake Control) module connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new TBC (Trailer Brake Control) module. CLEAR the DTCs. REPEAT the network test with the scan tool.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.