U0101–LOST COMMUNICATION WITH TCM

For a complete wiring diagram Refer to Section 8W.

When Monitored:

With the ignition on
Battery voltage between 10 and 16 volts
IOD fuse installed

Set Condition:
If the Anti-Lock Brakes Module fails to receive bus messages from the TCM for approximately 500 ms.

Possible Causes

CAN C BUS CIRCUITS OPEN OR SHORTED

TCM POWER AND GROUND

PCM DTCs PRESENT

TCM

ANTI-LOCK BRAKES MODULE

Diagnostic Test

1. VERIFY DTC IS ACTIVE

NOTE: Verify the IOD fuse is installed and battery voltage is between 10 and 16 volts before proceeding.

NOTE: If present, diagnose and repair DTC U0002–CAN C BUS OFF PERFORMANCE, DTC or DTC U1502–IMPLAUSIBLE MESSAGE DATA LENGTH RECEIVED FROM TIPM before diagnosing this DTC.

Turn the ignition on.
With the scan tool, read and record ABS DTCs.
With the scan tool, read and record Environmental Data (EV Data).
With the scan tool, erase ABS DTCs.
Cycle the ignition switch.
With the scan tool, read ABS DTCs.

Does this DTC reset?

Yes

Go To 2

Perform the Stored Lost Communication test procedure. Refer to the table of contents in this section. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING).
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

2. CHECK FOR ANY OF THE FOLLOWING ACTIVE DTCs

With the scan tool, read all active DTCs from all CAN C Bus modules.

NOTE: Check for CAN C hardware electrical, VIN Missing/Mismatch, battery or ignition related DTCs.

Does the scan tool display any active DTCs related to the conditions listed above?

Yes

Diagnose and repair the DTC(s). Refer to the Table of Contents in the applicable Section.

Go To 3

3. VERIFY THAT THE TCM IS ACTIVE ON THE BUS

With the scan tool, select ECU View.
Verify that the TCM is active on the bus.

Is the TCM active on the bus?

Yes

Go To 4

Refer to the Table of Contents located in this section for a no response test procedure.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

4. CHECK FOR ADDITIONAL COMMUNICATION RELATED DTCs

With the scan tool, select Network View and select Advanced.

Is there more than one module with active DTCs “Logged Against” the TCM?

Yes

Replace/update the TCM in accordance with the service information.

Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).

Replace the Anti-Lock Brakes Module in accordance with the service information.
Perform BODY VERIFICATION TEST – VER 1. (Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - STANDARD PROCEDURE).