DTC P0125: Coolant Temp Sensor Closed Loop Temp Not Met: Notes

A closed loop air/fuel metering system is used to provide best possible combination of driveability, fuel economy and emission control. Vehicle operates in open loop when first started, ignoring heated oxygen sensor signal and calculating air/fuel ratio based on inputs from engine coolant temperature, throttle position and mass airflow sensors only.

When oxygen sensor (sensor No. 1) has varying voltage output indicating that it is hot enough for proper operation, system will enter closed loop. Code P0125 will set when engine coolant temperature is sufficient to allow closed loop operation and closed loop is not achieved within 9 minutes of start-up.