U0121-LOST COMMUNICATION WITH ANTI-LOCK BRAKE MODULE
For a complete wiring diagram Refer to Section 8W.
- When Monitored:
Ignition run time is greater than 1 second. Battery voltage between 9 and 16 volts. Engine run time greater than 3 seconds.
- Set Condition:
The PCM doesn't receive an ABS message over the CAN C circuit for 7 consecutive seconds. The circuit is continuously monitored. One Trip fault.
| Possible Causes |
| CAN C BUS OPEN OR SHORTED CONDITION |
| ABS MODULE |
| FCM |
| PCM |
Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diagnostic procedures and for further possible causes.
Diagnostic Test
1. ACTIVE DTCIgnition on, engine not running.
With a scan tool, View PCM DTCs.
Is the DTC Active at this time?
Yes
- Refer to 8 - ELECTRICAL/ELECTRONIC CONTROL MODULES - DIAGNOSIS AND TESTING for diagnostic procedures and for further possible causes.
No
- Refer to the INTERMITTENT CONDITION Diagnostic Procedure.
- Perform the POWERTRAIN VERIFICATION TEST. (Refer to 9 - ENGINE - STANDARD PROCEDURE)