Test Procedure

DF1 CHECK FOR DTCS

Are DTCs P0500, P1501 and U0121 present?

Yes	No
For DTC U0121, REFER to the service information , Vehicle Dynamic Systems, DTC Charts, to continue diagnosis of DTC U0121. For all others, GO to DF2 .	GO to DF2 .

DF2 CHECK FOR OTHER DTCS

Carry out the ABS self-test.

Are any DTCs present?

Yes	No
REFER to the service information , Vehicle Dynamic Systems, DTC Charts.	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.	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) .	The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.