Speedometer Or Odometer Inoperative
- If instrument cluster diagnostic system check has been performed, go to next step. If instrument cluster diagnostic system check has not been performed, go to INSTRUMENT CLUSTER DIAGNOSTIC SYSTEM CHECK
under SELF-DIAGNOSTIC SYSTEM.
- Turn ignition off. Connect scan tool to Data Link Connector (DLC). See Figure
. Start engine and allow to idle. Select Powertrain Control Module (PCM) data display. Monitor VEHICLE SPEED parameter. Test drive vehicle. If VEHICLE SPEED parameter is not the same as speedometer, go to next step. If VEHICLE SPEED parameter is the same as speedometer, go to step 5
.
- Check for open, short to ground, short to voltage or high resistance in Dark Green/White wire between PCM connector C1 terminal No. 26 and Instrument Panel Cluster (IPC) connector C2 terminal A6. See Figure
and Fig 1
. If circuit is okay, go to next step. If faulty circuit is found and repaired, go to step 8
.
- Check for poor connections at IPC connector. If connections are okay, go to step 6
. If faulty connections are found and repaired, go to step 8
.
- Check for poor connections at PCM connector. If connections are okay, go to step 7
. If faulty connections are found and repaired, go to step 8
.
- Replace Instrument Panel Cluster (IPC). See INSTRUMENT PANEL CLUSTER
under REMOVAL & INSTALLATION. After repairs, go to next step.
- Replace PCM. See appropriate REMOVAL, OVERHAUL & INSTALLATION article in ENGINE PERFORMANCE. After repairs, go to next step.
- Recheck speedometer and/or odometer operation. If speedometer and/or odometer operate properly, repair is complete. If speedometer and/or odometer do not operate properly, go to step 2
.
Courtesy of GENERAL MOTORS CORP.