Troubleshooting

DTC P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control

CIRCUIT DESCRIPTION

DTC Detection Condition:

A thermistor built into the engine coolant temperature sensor changes the resistance value according to the engine coolant temperature.

The structure of the sensor and connection to the ECM is the same as in the intake air temperature circuit malfunction.

MONITOR DESCRIPTION

Monitor Strategy:

Typical Enabling Conditions:

Typical Malfunction Thresholds:

P0125
The ECM monitors the ECT signal voltage after engine start-up. If, after sufficient time has passed, the sensor
still reports that the engine is not warm enough for closed-loop fuel control, the ECM interprets this as a fault in the sensor or cooling system and sets a DTC.

Example:
The ECT is 0 °C (32 °F) at engine start. After 5 minutes running time, the ECT sensor still indicates that the engine is not warm enough to begin air fuel ratio feedback control of the air-fuel ratio. The ECM interprets this as a fault in the sensor or cooling system and will set a DTC.

Step 1 - 2:

INSPECTION PROCEDURE

HINT:
- If DTCs P0115, P0116 and P0125 are output simultaneously, engine coolant temperature sensor circuit may be open. Perform troubleshooting of DTC P0115 first.
- Read freeze frame data using hand-held tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.