U1120

U1120-LOST WHEEL DISTANCE MESSAGE





For the Engine circuit diagram, Refer to SCHEMATICS AND DIAGRAMS.

When Monitored
Ignition on.

Set Condition
The PCM doesn't receive a wheel distance message from the Anti-lock brake Module or FCM (NON-ABS) over the CAN C bus.

Possible Causes
- CAN C BUS CIRCUIT OPEN OR SHORTED
- ANTI-LOCK BRAKE MODULE
- PCM

Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding.

Theory of Operation
The PCM receives the vehicle speed signal over the CAN C bus from the Anti-lock Brake Module or FCM (NON-ABS).

Diagnostic Test
1. ACTIVE DTC





Ignition on, engine not running.
With the scan tool read Powertrain DTCs.

Is the DTC active at this time?
Yes >> Go To 2
No >> Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 5. Powertrain Verification Test - Ver 5
2. U0121-LOST COMMUNICATION WITH ABS MODULE/P0141-LOST COMMUNICATION WITH FCM ALSO SET

NOTE: If the vehicle is not equipped with ABS the VSS signal will come from the FCM.

With the scan tool, read the appropriate module for DTCs.

Is the U0121-LOST COMMUNICATION WITH ABS MODULE/P0141-Lost Communicate With FCM also set?
Yes >> Perform the appropriate diagnostic test.
Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 5. Powertrain Verification Test - Ver 5
No >> Replace and program the Powertrain Control Module per Service Information.
Perform (NGC) POWERTRAIN VERIFICATION TEST VER - 5. Powertrain Verification Test - Ver 5