Diagnostic Procedures
- If powertrain diagnostic system check was performed, go to next step. If powertrain diagnostic system check was not performed, go to POWERTRAIN DIAGNOSTIC SYSTEM CHECK under DIAGNOSTIC SYSTEM CHECKS. After performing powertrain diagnostic system check, go to next step.
- Check coolant level. If coolant level is low, repair any cooling system leaks and fill coolant to proper level. If coolant level is okay, go to next step.
- Turn ignition off. Disconnect ECT sensor. Connect a 3-amp fused jumper wire between ECT sensor connector terminals. Turn ignition on. Monitor ECT sensor temperature on scan tool. If scan tool indicates ECT value is more than 280°F (138°C), go to step 7. If scan tool indicates ECT value 280°F (138°C) or less, go to next step.
- Turn ignition off. Connect a 3-amp fused jumper wire between ECT sensor connector terminal "B" (Yellow wire) and ground. Turn ignition on. Monitor ECT sensor temperature on scan tool. If scan tool indicates ECT value is more than 280°F (138°C), go to next step. If scan tool indicates ECT value is 280°F (138°C) or less, go to step 6.
- Check for open or high resistance in Brown wire between ECT sensor connector terminal "A" and PCM connector C1 terminal No. 12. Repair wiring as necessary. After repairs, go to step 10.
- Check for open or high resistance in Yellow wire between ECT sensor connector terminal "B" and PCM connector C2 terminal No. 26. Repair wiring as necessary. After repairs, go to step 10.
- Remove ECT sensor. Using a pan of hot water, check ECT sensor temperature/resistance. See appropriate SENSOR OPERATING RANGE CHARTS article. If ECT sensor closely matches sensor operating range chart, go to next step. If ECT sensor does not closely match sensor operating range chart, go to step 9.
- Reinstall ECT sensor and diagnose thermostat. See appropriate article in ENGINE COOLING.
- Replace ECT sensor. See REMOVAL, OVERHAUL & INSTALLATION - CARS article. After replacing ECT sensor, go to next step.
- Using scan tool, clear DTCs. Turn ignition off for 30 seconds. Start engine and allow it to reach normal operating temperature. Operate vehicle within conditions for setting this DTC in code enable criteria. If scan tool indicates that this test ran and passed, go to next step. If scan tool does not indicate that this test ran and passed, go to step 2.
- Using scan tool, select CAPTURE INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, go to applicable DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If no undiagnosed DTCs are displayed, system is okay.