Procedure F, Speed Sensor Circuit (Instrument Cluster)
- Speedometer Cable: If speedometer needle fluctuates when driving at a steady speed, replace faulty speedometer cable. If speedometer needle does not fluctuate, ensure ignition switch is off and go to next step.
- Speed Sensor: Disconnect instrument cluster connector. Check continuity between wiring harness side of speed sensor terminal No. 3 (White/Black wire) and ground. See Figure for terminal identification. If continuity exists, go to next step. If no continuity exists, repair wiring harness open circuit between terminal No. 3 (White/Black wire) and ground.
- Check speed sensor operation. See SPEED SENSOR TEST under TESTING in this article. If speed sensor is faulty, replace sensor and recheck cruise control system. If speed sensor is okay, go to next step.
- Turn ignition on. Check for 5-volt reference voltage between ECU terminal No. 8 (Violet/Yellow wire) and ground. If voltage is correct, go to next step. If voltage is incorrect, power source or ECU is faulty. Recheck power source circuit using PROCEDURE A, POWER SOURCE CIRCUIT.
- Check for 5-volt reference voltage between wiring harness side of speed sensor terminal No. 10 (Violet/Yellow wire) and ground. If voltage is correct, turn ignition off and go to next step. If voltage is incorrect, repair wiring harness short circuit between speed sensor terminal No. 10 (Violet/Yellow wire) and ECU terminal No. 8 (Violet/Yellow wire).
- Cruise Control ECU: Disconnect electronic control unit. Check continuity between wiring harness side of speed sensor terminal No. 10 (Violet/Yellow wire) and wiring harness side of ECU terminal No. 8 (Violet/Yellow wire). If continuity exists, replace faulty ECU and recheck cruise control system. If no continuity exists, repair wiring harness open circuit between speed sensor terminal No. 10 (Violet/Yellow wire) and ECU terminal No. 8 (Violet/Yellow wire).