DTC P0125: ECT Sensor Malfunction/Slow Response

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.
Check the ECT SENSOR in the DATA LIST with the HDS.
Is about 86°F (30°C) or less, or 2.61 V or more indicated?
1. YES- Go to step 3.
2. NO- Intermittent failure, system is OK at this time. Check the thermostat and the cooling system.
Let the engine idle for 20 minutes.
Check the ECT SENSOR in the DATA LIST with the HDS.
Is about 86°F (30°C) or less, or 2.61 V or more indicated?
1. YES- Go to step 5.
2. NO- Intermittent failure, system is OK at this time. Check the thermostat and the cooling system.
Turn the ignition switch OFF.
Replace the ECT sensor (see ECT SENSOR REPLACEMENT ).
Turn the ignition switch ON (II).
Reset the ECM/PCM with the HDS.
Do the ECM/PCM idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
Allow the engine to cool to between 23°F (-5°C) and 77°F (25°C).
Start the engine, and let it idle 20 minutes.
Check for Temporary DTCs or DTCs with the HDS.
Are any Temporary DTCs or DTCs indicated?
1. YES- If DTC P0125 is indicated, check for poor connections or loose terminals at the ECT sensor and the ECM/PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.
2. NO- Go to step 13.
Monitor the OBD STATUS for DTC P0125 in the DTCs MENU with the HDS.
Does the screen indicate PASSED?
1. YES- Troubleshooting is complete.
2. NO- If the screen indicates FAILED, check for poor connections or loose terminals at the ECT sensor and the ECM/PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 10 and recheck.