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Test D: Speedometer/Odometer Inaccurate

  1. Turn ignition off. Connect scan tool and retrieve Diagnostic Trouble Codes (DTC) following manufacturer's instructions. If no DTCs are present, go to next step. If DTCs are present, see appropriate TESTS W/CODES article in the ENGINE PERFORMANCE section. Repair DTCs as necessary, then retest system.
  2. Using scan tool, observe Vehicle Speed Sensor (VSS) output Parameter Identification (PID) while assistant drives vehicle over range of speeds on various road surfaces. If VSS PID varies smoothly with vehicle speed, go to next step. If VSS PID does not vary or is erratic, see appropriate TESTS W/CODES article in the ENGINE PERFORMANCE section to diagnose VSS.
  3. Remove and check OBDII 10-amp fuse in engine compartment fuse box. If fuse is okay, reinstall fuse and go to step 5). If fuse is blown, go to next step.
  4. Turn ignition off. Remove instrument cluster. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Disconnect instrument cluster electrical connectors. Measure resistance between ground and instrument cluster harness connector C253 terminal No. 1 (Green wire). See Figure and Figure . Resistance should be more than 10 k/ohms. If resistance is more than 10 k/ohms, replace OBDII 10-amp fuse and go to next step. If resistance is less than 10 k/ohms, repair Green wire between instrument cluster harness connector and fuse. See WIRING DIAGRAMS  .
  5. Turn ignition off. Remove instrument cluster. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION. Disconnect instrument cluster electrical connectors. Measure voltage between ground and instrument cluster harness connector C253 terminal No. 1 (Green wire). See Figure and Figure . Voltage should be more than 10 volts. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair Green wire between instrument cluster harness connector and fuse. See WIRING DIAGRAMS  .
  6. Turn ignition off. Disconnect Vehicle Speed Sensor (VSS) harness connector. Measure resistance of Blue wire between VSS harness connector and instrument cluster harness connector C252 terminal No. 11. See Figure . Measure resistance of White/Black wire between VSS harness connector and instrument cluster harness connector C252 terminal No. 1. Resistance in both tests should be less than 5 ohms. If resistances are as specified, go to next step. If resistances are not as specified, repair wire in question. See WIRING DIAGRAMS  .
  7. Measure resistance between ground and instrument cluster harness connector C252 terminal No. 1 (White/Black wire). Measured resistance should be more than 10 k/ohms. If resistance is more than 10 k/ohms, go to next step. If resistance is less than 10 k/ohms, repair short in White/Black wire.
  8. Turn ignition on. Measure voltage between ground and instrument cluster harness connector C252 terminal No. 12 (Black/Yellow wire). See Figure . Voltage should be more than 10 volts. If voltage is more than 10 volts, go to next step. If voltage is less than 10 volts, repair Black/Yellow wire between instrument cluster connector and fuse. See WIRING DIAGRAMS  .
  9. Turn ignition off. Visually inspect instrument cluster printed circuit for damage, cracks or hot spots. If instrument cluster printed circuit is okay, replace speedometer. If instrument cluster printed circuit is damaged, replace printed circuit and gauge contact clips. See PRINTED CIRCUIT  under REMOVAL & INSTALLATION.
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