Test Description
WARNING: This page is about a different car, the 2003 Pontiac Sunfire and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.
The numbers below refer to the step numbers on the diagnostic table.
4. The vehicle speed detector in the PCM and the VSS are matched so that an open or a short to ground in the VSS low signal circuit will not usually cause a loss of speed signal or a DTC P0502 to set.
7. This step isolates the short between the VSS and the wiring.
9. The DMM will detect AC voltage if the VSS high signal circuit is shorted to ground.