Test Description

WARNING: This page is about a different car, the 2003 GMC Sonoma and 2003 Chevrolet S10 Pickup. 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.

5. The resistance measurement will not change if either the VSS high signal circuit or the VSS low signal circuit, but not both, is shorted to ground. The vehicle speed detector in the PCM and the VSS are matched in such a way 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.
8. This step isolates the short between the VSS and the wiring.
10. The DMM will detect AC voltage if the VSS high signal circuit is shorted to ground.

Fig 1: DTC P0502 (1 Of 2)
Courtesy of GENERAL MOTORS CORP.

Fig 2: DTC P0502 (2 Of 2)

Courtesy of GENERAL MOTORS CORP.