Vehicle Speed Sensor (VSS) No. 1 Circuit (Speedometer Operates)

If odometer does not operate, repair as necessary. See appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT section. If odometer operates, remove instrument cluster, leaving electrical connectors attached.
Raise and support vehicle with rear wheels off of ground. Turn ignition on. Backprobing connector, connect voltmeter between ground and terminal No. 2 (Orange wire) at instrument cluster 16-pin connector. See Fig 2. Rotate drive shaft.
If voltage does not alternate between zero and 5 or more volts for each revolution of drive shaft, replace printed circuit plate and retest. If voltage alternates between zero and 5 or more volts, check for faulty Orange wire between instrument cluster and ECM. See appropriate wiring diagram in WIRING DIAGRAMS article. If wire is okay, replace ECM.

Fig 1: Identifying Instrument Cluster 23-Pin Connector Terminals

Fig 2: Identifying Instrument Cluster 16-Pin Connector Terminals