DTC P0125: Insufficient Coolant Temperature For Closed Loop Fuel Control (Esteem 1.8L)
- Turn ignition off. Install scan tool. Start engine and allow it to reach normal operating temperature. Using scan tool, check coolant temperature. If coolant temperature is less than 88°F (31°C), go to next step. If coolant temperature is greater than 88°F (31°C), go to step 4 .
- Ensure ignition is off. Connect jumper wire between ECT sensor connector Light Green/Red and Orange terminals. Turn ignition on. Check coolant temperature on scan tool. If coolant temperature is 401°F (205°C), go to next step. If coolant temperature is not 401°F (205°C), check for open circuit in Light Green/Red or Orange wires. If wiring is okay, replace PCM.
- Drain coolant. Disconnect ECT sensor harness connector and remove sensor from engine. Measure resistance between ECT sensor terminals while immersed in a container of water. Heat water slowly and ensure resistance changes as specified. Go to ENGINE COOLANT TEMPERATURE (ECT) SENSOR under ENGINE SENSORS & SWITCHES in SYSTEM & COMPONENT TESTING article. If resistance is not as specified, replace ECT sensor. If resistance is as specified, check for high circuit resistance. See appropriate wiring diagram in WIRING DIAGRAMS article. If wiring and connectors are okay, replace PCM.
- Check thermostat operation. If heater takes a long time to become effective, or coolant flows into radiator on cold start, remove thermostat for inspection. Replace as necessary and retest system. If thermostat operates properly, go to next step.