Pinpoint Test G: DTC U0100

Auxiliary Brake System - Trailer Brake Control (TBC) Module

Pinpoint Tests

Pinpoint Test G: DTC U0100

Normal Operation
- DTC U0100 (Lost Communication With ECM/PCM "B") - this DTC sets in continuous memory or on-demand 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 Module Communications Network Testing and Inspection.

This pinpoint test is intended to diagnose the following:


- PCM
- TBC module

PINPOINT TEST G: DTC U0100

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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 Module Communications Network Testing and Inspection to diagnose no communication with the PCM.

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G2 CHECK THE TBC MODULE CONTINUOUS MEMORY DTCs

- Ignition ON.
- Enter the following diagnostic mode on the scan tool: TBC Module Self-Test.
- Clear the DTCs. Repeat the TBC 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.

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G3 RETRIEVE THE RECORDED DTCs FROM THE TBC MODULE SELF-TEST

- Check for recorded TBC module DTCs from the self-test.
- Is DTC B1317 or DTC B1318 recorded?

Yes
For DTC B1317, GO to Pinpoint Test D. For DTC B1318, GO to Pinpoint Test E. Pinpoint Test D: DTC B1317 Pinpoint Test E: DTC B1318

No
GO to G4.

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G4 RETRIEVE THE RECORDED DTCs FROM THE PCM SELF-TEST

- Check for recorded PCM DTCs from the self-test.
- Is DTC P0562 or DTC P0563 recorded?

Yes
REFER to Electronic Engine Controls Testing and Inspection.

No
GO to G5.

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G5 CHECK FOR DTC U0100:00 SET IN OTHER MODULES

- Ignition ON.
- Retrieve the continuous memory DTCs from the following modules:
- Accessory Protocol Interface Module (APIM) (if equipped)
- BCM
- Instrument Panel Cluster (IPC)
- Occupant Classification System Module (OCSM)
- Power Steering Control Module (PSCM) (if equipped)
- Restraints Control Module (RCM)
- Transfer Case Control Module (TCCM) (if equipped)
- Is DTC U0100:00 set in any of these modules?

Yes
INSTALL a new PCM. REFER to Electronic Engine Controls Service and Repair.

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

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