Inspection Procedure

HINT:

• If any of DTCs P0115, P0116, P0117 or P0118 are set 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. The ECM records vehicle and driving condition information as freeze frame data the moment a DTC is stored. 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 OTHER DTCS OUTPUT (IN ADDITION TO DTC P0125) 
   1. Connect an 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 

   OTHER DTCS OUTPUT (IN ADDITION TO DTC P0125)
   
   

   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  DIAGNOSTIC TROUBLE CODE 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: 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 INSTALLATION ).

      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.

   OK : 

   There is no modification of cooling system. 

   NG : REPAIR OR REPLACE COOLING SYSTEM 

   OK : REPLACE ENGINE COOLANT TEMPERATURE SENSOR