Pinpoint Test G: DTC U0100

Auxiliary Brake System - Trailer Brake Control (TBC) Module

Pinpoint Test G: DTC U0100

Normal Operation

- DTC U0100 (Lost Communication With ECM/PCM)- sets in the Trailer Brake Control (TBC) module if data messages received (vehicle speed) from the PCM are missing for more than 5 minutes. For a complete list of all network messages, refer to Information Bus.

This pinpoint test is intended to diagnose the following:

- PCM

- TBC (Trailer Brake Control) module

PINPOINT TEST G : DTC U0100

G1 VERIFY THE SCAN TOOL CAN COMMUNICATE WITH THE PCM

- Connect the scan tool.

- Ignition ON.

- Check that a vehicle session can be established using the scan tool.

Can a vehicle session be established?

Yes
GO to G2.

No
REFER to Information Bus to diagnose no communication with the PCM.

G2 CHECK THE TBC (Trailer Brake Control) MODULE CONTINUOUS MEMORY DTCs

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: TBC (Trailer Brake Control) Module Self-Test.

- Clear the DTCs. Repeat the TBC (Trailer Brake Control) module self-test.

Is DTC U0100 retrieved again?

Yes
GO to G3.

No
The system is operating correctly at this time. The DTC may have been set due to high network traffic or an intermittent fault condition.

G3 RETRIEVE THE RECORDED DTCs FROM THE TBC (Trailer Brake Control) MODULE SELF-TEST

- Check for recorded TBC (Trailer Brake Control) module DTCs from the self-test.

Is DTC B1317 or DTC B1318 recorded?

Yes
For DTC B1317, GO to Pinpoint Test D. Pinpoint Test D: DTC B1317

For DTC B1318, GO to Pinpoint Test E. Pinpoint Test E: DTC B1318
No
GO to G4.

G4 CHECK FOR DTC U0100 SET IN OTHER MODULES

- Ignition ON.

- Retrieve the continuous memory DTCs from all modules.

Is DTC U0100 or DTC U0100:87 set in other modules?

Yes
INSTALL a new PCM. TEST the system for normal operation.

No
INSTALL a new TBC (Trailer Brake Control) module. REFER to Trailer Brake Control (TBC) Module . TEST the system for normal operation.