Diagnosis & Repair Procedure
- If engine system check has been performed, go to next step. If engine system check has not been performed, go to A4: ENGINE SYSTEM CHECK under SYSTEM TESTS.
- Turn ignition off. Disconnect ECT sensor No. 2 2-pin harness connector. ECT sensor is located in thermostat housing. See Figure . Turn ignition on. Measure voltage between ground and ECT sensor No. 1 (Light Green wire). Voltage should be 4-5 volts. If voltage is not as specified, go to next step. If voltage is as specified, leave harness connector disconnected and go to step 4 .
- Repair short to ground in Light Green wire between ECM and ECT sensor No. 2. After repair, repeat DTC CONFIRMATION PROCEDURE .
- Turn ignition off. Disconnect ECM 16-pin harness connector C20. ECM is located under instrument panel, behind glove box. See Figure . Check continuity of Green/Red wire between ECT sensor No. 2 and ECM. See Figure and WIRING DIAGRAMS article. If continuity exists, go to step 6 . If no continuity exists, go to next step.
- Repair short to ground in Green/Red wire between ECM and ECT sensor No. 2. After repair, repeat DTC CONFIRMATION PROCEDURE .
- Check ECT sensor No. 2 operation. See appropriate procedure under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article. If problem is found, replace ECT sensor No. 2. After repair, repeat DTC CONFIRMATION PROCEDURE . If no problem is found, problem is probably intermittent. See INTERMITTENTS in TROUBLE SHOOTING - NO CODES article. If no intermittent problem is found, go to next step.
- Substitute a known good ECM, and repeat DTC CONFIRMATION PROCEDURE . If DTC does not reset, testing is complete.