P0125 - INSUFFICIENT COOLANT TEMPERATURE FOR CLOSED LOOP FUEL CONTROL

The DTC code P0125 OBD2 means that the ECM (Engine Control Module) has detected that the heat in the cooling system is not sufficient, so that the fuel management system can take control. The ECM (Engine Control module) has a default value, so that after the engine starts, there is a coolant temperature.

Basically this diagnostic code indicates that the ECT sensor (Coolant temperature sensor) has not reached the temperature level that is needed to enter the closed loop operation in a specific time lapse.

• Check Engine light on.
• Poor fuel economy.
• Engine overheating.

The reasons why the code P0125 OBD II can be established are the following:

• The warm-up time may not be enough. The coolant level may be below the required level.
• Perhaps the engine coolant thermostat leaks or does not open at the proper temperature.
• The cable system from the ECT sensor (Engine Coolant Temperature) to the ECM (Engine Control module) may be defective.
• Corrosion in the Coolant Temperature Sensor (ECT) connector.
• The ECT sensor may be defective.

For fault code P0125 you can follow these repair and diagnostic steps:

• First, check the coolant level.
• Proceed to check the thermostat and make sure it is opening correctly.
• Inspect the cables and connectors corresponding to the ECT sensor. Check that they are in good condition and do not wear or rub with any component. Repair or replace any of these in case of finding inconsistencies.
• You can change the Coolant Temperature Sensor (ECT).