Test Procedure
- DF1 CHECK FOR DIAGNOSTIC TROUBLE CODES (DTCS)
Is DTC U0121 present?
Yes No REFER to the appropriate Vehicle Dynamic Systems article, 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 appropriate Vehicle Dynamic Systems article 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.