Diagnostic Aids
When diagnosing an intermittent problem, use scan tool to review malfunction history diagnostic information. This data can be used to duplicate a problem.
The speedometer will not work if the VSS sub-system has failed. VSS resistance should be between 800-1600 ohms. If problem is intermittent, wiggle wires while monitoring VSS signal on scan tool and watch for signal to jump or go away. PCM will calculate VSS based on RPM and TP sensor signal if DTC P0500 is present, but speedometer will remain inoperative.