P0125 - Insufficient Coolant Temperature for Closed Loop Fuel Control

System Information

Engine Coolant Temperature is monitored to allow the ECM to accurately adjust fueling and emission control systems, it will also normally be used to control cooling fan operation.

Fault Code Explained

The ECM has detected that the Engine Coolant Temperature as indicated by the ECT sensor has not reached sufficient temperature for Closed Loop Fuel Control to occur quickly enough after engine start.

Recommended Tests

If possible use a diagnostic computer to view live data for the ECT sensor and compare to actual engine coolant temperature.

If the Actual Coolant Temperature matches the sensor value and the engine is running colder than normal it is recommended to carry out cooling system checks to establish reason for cold running

If the actual engine coolant temperature does not match the sensor value it is recommended to check the sensor and sensor wiring