Antilock Brake/Traction Control System

U0101-LOST COMMUNICATION WITH TCM

- 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
- DTCs RELATED TO BATTERY VOLTAGE, IGNITION, OR VIN MESSAGES
- PCI BUS CIRCUITS OPEN OR SHORTED
- CAN C BUS CIRCUITS OPEN OR SHORTED
- TCM POWER AND GROUND
- BCM DTCs PRESENT
- TCM
- ANTI-LOCK BRAKES MODULE

Diagnostic Test
1. VERIFY DTC IS ACTIVE

NOTE: Ensure 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 U0146-LOST COMMUNICATION WITH CENTRAL GATEWAY, or DTC U1502-IMPLAUSIBLE MESSAGE DATA LENGTH RECEIVED FROM FCM / BCM 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
No >> Perform the Stored Lost Communication test 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).
No >> 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
No >> Refer to Body Control Systems for No Response related diagnostic procedures. Testing and Inspection

4. CHECK IF BCM DTCs ARE PRESENT
With the scan tool, read BCM DTCs.
Are any BCM DTCs present?
Yes >> Diagnose and repair the DTC(s). Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
No >> Go To 5

5. 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. Perform 45RFE/545RFE TRANSMISSION VERIFICATION TEST - VER 1. Transmission Verification Test Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test
No >> Replace the Anti-Lock Brakes Module. Perform ABS VERIFICATION TEST - VER 1. ABS Verification Test