Diagnostic Procedures
- Install scan tool. Ensure engine coolant temperature is less than 203°F (95°C). Start engine. Check if DTC P1691 is active. If DTC is active, go to next step. If DTC is not active, problem is intermittent. See DIAGNOSTIC AIDS.
- Using scan tool, review malfunction history to determine fault type. If fault type indicates that circuit is open/grounded, go to next step. If fault type indicates that circuit is shorted, go to step 5). If fault type indicates that circuit is intermittent, check circuits for proper routing and terminals for proper tightness.
- Turn ignition off. Disconnect PCM harness connector J1. Turn ignition on. Check voltage in circuit between temperature gauge and PCM. If battery voltage is present, check for terminal tightness at PCM or faulty PCM. If battery voltage is not present, go to next step.
- Check circuit between temperature gauge and PCM for open, short to ground, terminal tightness at harness connector and gauge. If circuit and connectors are okay, service instrument cluster.
- Turn ignition off. Disconnect instrument panel harness connector. Turn ignition on. Use scan tool to check if shorted condition still exist. If a short is still indicated, check circuit between temperature gauge and PCM for short to voltage or faulty PCM. If short condition is not indicated, check for shorted circuit to temperature gauge or faulty gauge.