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Speedometer & Odometer Inoperative

  1. Use DVOM and check for continuity in Pink/Black wire between ground and instrument cluster connector I-10 terminal No. 21 (connector I-9 terminal No. 19 on "S" model). See Fig 1 . If continuity is indicated, go to next step. If continuity is not indicated, repair open in Pink/Black wire or poor ground connection located in right rear of engine compartment, bolted to inner fender.
  2. Disconnect Vehicle Speed Sensor (VSS). Use DVOM and check for continuity between VSS connector terminal No. 2 (Black/Red wire) and ground. See WIRING DIAGRAMS  . If continuity is indicated, go to step 4). If continuity is not indicated, go to next step.
  3. Repair open in Black/Red wire or poor ground connection located in right rear of engine compartment, bolted to inner fender.
  4. Turn ignition switch to ON position. Use DVOM and measure voltage between ground and VSS connector terminal No. 1 (Blue/Yellow wire). See WIRING DIAGRAMS  . If battery voltage is indicated, go to step 6). If battery voltage is not indicated, go to next step.
  5. Repair open in Blue/Yellow wire and go back to step 4)
  6. Disconnect instrument cluster connector I-10. Use DVOM and check continuity between instrument cluster connector I-10 terminal No. 5 and VSS connector terminal No. 3 (Light Green/White wire). See WIRING DIAGRAMS  . If continuity is indicated, go to step 8). If continuity is not indicated, go to next step.
  7. Repair open in Light Green/White wire. Recheck system operation.
  8. Lift and support drive wheels of vehicle. Remove instrument cluster and disconnect connector I-9. Connect a resistance of 1.3 to 5 ohms (1.4 watts or more) between Blue/Yellow wire of connector I-9 terminal No. 15 (terminal No. 26 on "S" models) and instrument cluster connector I-10 terminal No. 5 (Light Green/White wire). See Fig 1 .
  9. Install a speedometer tester. Start vehicle and bring speed up to 37 MPH. Check waveform from VSS with oscilloscope. Normal waveforms are between approximately 12 volts to 2 volts with a cycle of 23.6 milliseconds. If waveforms are normal, replace speedometer assembly. See INSTRUMENT CLUSTER  under REMOVAL & INSTALLATION.
  10. If waveforms are not normal, check for open/shorted wires or poor connections between VSS and instrument cluster and repair as necessary. See WIRING DIAGRAMS  . If all circuits and connectors are okay, replace VSS. See VEHICLE SPEED SENSOR (VSS) under REMOVAL & INSTALLATION.
Fig 1: Identifying Instrument Cluster Connector Terminals
G98B04013Courtesy of ISUZU MOTOR CO.
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