Pinpoint Test AJ: DTC U0121 - Lost Communication With Anti-Lock Brake System (Abs) Control Module
WARNING: This page is about a different car, the 2008 Ford RV Cutaway, 2008 Ford Econoline, 2008 Ford E450 Super Duty, and 2008 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
- AJ1 RETRIEVE THE RECORDED DTCs FROM BOTH THE CONTINUOUS AND ON-DEMAND INSTRUMENT CLUSTER (IC) SELF-TESTS
- Check for recorded instrument cluster (IC) DTCs from the continuous and on-demand self-tests.
- Is DTC B1318 recorded?
- YES : Go to Pinpoint Test AF .
- NO : Go to AJ2.
- AJ2 RECHECK THE INSTRUMENT CLUSTER (IC) DTCs
- Key in ON position.
- Enter the following diagnostic mode on the diagnostic tool: Instrument Cluster (IC) Self-Test
- Clear the DTCs. Repeat the instrument cluster (IC) self-test.
- Is DTC U0121 still present?
- YES : Go to AJ3.
- NO : The system is operating correctly at this time. The DTC may have been set due to high network traffic.
- AJ3 CHECK THE PCM FOR DTC U0121
- Enter the following diagnostic mode on the diagnostic tool: PCM Key On Engine Off (KOEO) Self-Test
- Carry out the KOEO self-test for the PCM.
- Is DTC U0121 retrieved?
- YES : REFER to MODULE COMMUNICATIONS NETWORK article to diagnose no communication with the ABS module.
- NO : Go to AJ4.
- AJ4 CHECK FOR CORRECT INSTRUMENT CLUSTER (IC) OPERATION
- Disconnect the instrument cluster (IC) connector.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect the instrument cluster (IC) connector and make sure it seats correctly.
- Operate the system and verify the concern is still present.
- Is the concern still present?
- YES : INSTALL a new instrument cluster (IC). REFER to Instrument Cluster (IC) . TEST the system for normal operation.
- NO : The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.