P0125

DTC P0125: ECT Sensor 1 Malfunction/Slow Response

1. Start the engine, and let it idle for 5 minutes or more.
2. Check ECT SENSOR 1 in the DATA LIST with the HDS.

Is about 10 °F (-12 °C) or less, or 4.45 V or more indicated?

YES - Go to step 9.

NO - Go to step 3.

3. Allow the engine to cool to 104 °F (40 °C) or less.
4. Note the value of ECT SENSOR 1 and ECT SENSOR 2 in the DATA LIST with the HDS.
5. Start the engine, and let it idle.
6. Let the engine idle until ECT SENSOR 1 goes up 49 °F (27 °C) or more from the recorded temperature.
7. Note the value of ECT SENSOR 2 in the DATA LIST with the HDS.
8. Compare ECT SENSOR 2 and the recorded temperature.

Does ECT SENSOR 2 change 17 °F (9.5 °C) or more?

YES - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the ECT sensor 1, the ECT sensor 2 and the PCM.

NO - Check the thermostat, then go to step 9.

9. Turn the ignition switch OFF.
10. Replace ECT sensor 1.
11. Turn the ignition switch ON (II).
12. Reset the PCM with the HDS.
13. Do the PCM idle learn procedure.
14. Allow the engine to cool to outside temperature.
15. Start the engine, and let it idle for 20 minutes.
16. Check for Temporary DTCs or DTCs with the HDS.

Are any Temporary DTCs or DTCs indicated?

YES - If DTC P0125 is indicated, check for poor connections or loose terminals at the ECT sensor 1, the ECT sensor 2, and the PCM, then go to step 1. If any other Temporary DTCs or DTCs are indicated, go to the indicated DTC's troubleshooting.

NO - Go to step 17.

17. Monitor the OBD STATUS for DTC P0125 in the DTCs MENU with the HDS.

Does the screen indicate PASSED?

YES - Troubleshooting is complete.

NO - If the screen indicates FAILED, check for poor connections or loose terminals at the ECT sensor 1, the ECT sensor 2, and the PCM, then go to step 1. If the screen indicates NOT COMPLETED, go to step 14 and recheck.