Note. Before you troubleshoot, record all freeze data and any on-board snapshot, and review the general troubleshooting information (see GENERAL TROUBLESHOOTING INFORMATION ).
- Start the engine, and let it idle for 5 minutes or more.
- Check ECT SENSOR 1 in the DATA LIST with the HDS. Is about 0°F(-18°C) or less indicated? YES -Check for poor connections or loose terminals at ECT sensor 1, ECT sensor 2, and the ECM/PCM. If they are OK, replace ECT sensor 1 (see «ECT SENSOR 1 REPLACEMENT»(ref-423675-S12151139802011092800000) ), then go to step 7 . NO -Go to step 3.
- Turn the ignition switch to LOCK (0).
- Allow the engine to cool to 104°F (40°C) or less.
- Start the engine, and let it idle until ECT SENSOR 1 goes up to about 158°F (70°C). Does ECT SENSOR 2 also read about 158°F (70°C)? YES -Go to step 6. NO -Intermittent failure, the system is OK at this time. Check for poor connections or loose terminals at ECT sensor 1, ECT sensor 2, and the ECM/PCM.
- Check the thermostat (see «FAN MOTOR TEST»(ref-423681-S06697072112011092800000) ). Is the thermostat OK? YES -Check for poor connections or loose terminals at ECT sensor 1, ECT sensor 2, and the ECM/PCM. If they are OK, replace ECT sensor 1 (see «ECT SENSOR 1 REPLACEMENT»(ref-423675-S12151139802011092800000) ), then go to step 7. NO -Replace the thermostat (see «THERMOSTAT REPLACEMENT»(ref-423681-S20229574382011092800000) ), then go to step 7.
- Turn the ignition switch to ON (II).
- Reset the ECM/PCM with the HDS.
- Turn the ignition switch to LOCK (0).
- Allow the engine to cool to 104°F (40°C) or less.
- Start the engine, and let it idle until ECT SENSOR 1 goes up to about 158°F (70°C). Does ECT SENSOR 2 also read about 158°F (70°C)? YES -Go to step 1 and recheck. NO -Troubleshooting is complete.