Test Procedure
- DF1 CHECK FOR DTCS
Is DTC U0121 present?
Yes No REFER to the service information , Vehicle Dynamic Systems, Symptom Charts, No communication with the ABS module. GO to DF2 . - DF2 VISUAL INSPECTION
- Carry out the ABS self-test.
Are any DTCs present?
Yes No REFER to the service information , Vehicle Dynamic Systems, to continue diagnosis of the ABS. GO to DF3 . - DF3 CHECK THE PCM VEHICLE SPEED SIGNAL INPUT WARNING: STRICT OBSERVANCE OF POSTED SPEED LIMITS AND ATTENTION TO DRIVING CONDITIONS ARE MANDATORY WHEN CARRYING OUT THE ROAD TEST. FAILURE TO FOLLOW THESE INSTRUCTIONS MAY RESULT IN PERSONAL INJURY.
- Access the PCM and monitor the VSS (SPD) PID.
- Road test the vehicle while monitoring the VSS PID.
Does the VSS PID increase and decrease while driving?
Yes No The concern is not present at this time. CHECK for a loose connection, and damaged or corroded terminals. WIGGLE the harness attempting to recreate the concern. REPAIR as necessary.
Clear the PCM DTCs. REPEAT the self-test.GO to DF4 . - DF4 CHECK FOR CORRECT PCM OPERATION
- Disconnect all the PCM connectors.
- Visually inspect for:
- pushed out pins
- corrosion
- Connect all the PCM connectors and make sure they seat correctly.
- Carry out the PCM self-test.
- Verify the concern is still present.
Is the concern still present?
Yes No INSTALL a new PCM. REFER to FLASH ELECTRICALLY ERASABLE PROGRAMMABLE READ ONLY MEMORY (EEPROM) , Programming the VID Block for a Replacement PCM. The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.