DTC P0125: ECT Sensor 1 Malfunction/Slow Response
- 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 PCM. If they are OK, replace ECT SENSOR 1 (see ECT SENSOR 1 REPLACEMENT .
NO - Go to step 3.
- Turn the ignition switch to LOCK (0).
- Allow the engine to cool to 104°F (40°C) or less.
- Make sure the temperature difference of ECT SENSOR 1 and ECT SENSOR 2 is between about 50 °F (10 °C) in the DATA LIST with the HDS.
- Start the engine, and let it idle until ECT sensor 1 goes up around 158 °F (70 °C).
Dose the ECT sensor 2 also show about 158 °F (70 °C)?
YES - Go to step 7.
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 PCM .
- Check the thermostat.
Is the thermostat OK?
YES - Check for poor connections or loose terminals at ECT SENSOR 1, ECT SENSOR 2, and the PCM. If they are OK, replace ECT SENSOR 1 (see ECT SENSOR 1 REPLACEMENT ), then go to step 8
NO -Replace the thermostat (see THERMOSTAT REPLACEMENT ), then go to step 8.
- Turn the ignition switch to LOCK (0).
- Allow the engine to cool 104 °F (40 °C) or less..
- Check the temperature difference of ECT SENSOR 1 and ECT SENSOR 2 is between about 50 °F (10 °C) in the DATA LIST with the HDS.
- Start the engine, and let it idle until ECT sensor 1 goes up around 158 °F (70 °C).
Dose the ECT sensor 2 also show about 158 °F (70 °C)?
YES - Go to step 1 and recheck. .
NO - Troubleshooting is complete.