DTC P0125 Insufficient Coolant Temperature for Closed Loop Fuel Control: Wiring Diagram

Refer to DTC P0115  ).

HINT:

• If any of DTCs P0115, P0116, P0117 or P0118 are set output simultaneously with DTC P0125, the Engine Coolant Temperature (ECT) sensor may have an open or a short circuit. Troubleshoot those DTCs first.
• Read freeze frame data using the intelligent tester. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, freeze frame data can help determine if the vehicle was running or stopped, if the engine was warmed up or not, if the air-fuel ratio was lean or rich, and other data from the time the malfunction occurred.

1. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0125) 
   1. Connect the intelligent tester to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the tester ON.
   4. Enter the following menus: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
   5. Read DTCs.

   Result 

   RESULT CHART
   
   

   Display (DTC Output)	Proceed to
   P0125	A
   P0125 and other DTCs	B

   HINT:

   If any DTCs other than P0125 are output, troubleshoot those DTCs first.

   B : GO TO RELEVANT DTC CHART 

   A : Go to next step 

2. INSPECT THERMOSTAT 
   1. Remove the thermostat (see REMOVAL ).
   2. Check the valve opening temperature of the thermostat.

      Standard temperature: 

      80 to 84°C (176 to 183°F) 

      HINT:

      In addition to the above check, confirm that the valve is completely closed when the temperature is below the standard.

   3. Reinstall the thermostat (see REMOVAL ).

   NG : REPLACE THERMOSTAT 

   OK : Go to next step 

3. CHECK COOLING SYSTEM 
   1. Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or any modifications.

   NG : REPAIR OR REPLACE COOLING SYSTEM 

   OK : REPLACE ENGINE COOLANT TEMPERATURE SENSOR