Inspection Procedure

HINT:

• If any of DTCs P0115 and P0116 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 a hand-held tester or OBD II scan tool. Freeze frame data record the engine condition when malfunctions are detected. When troubleshooting, freeze frame data can help determine if the vehicle was moving or stationary, 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. Are there any other codes (besides DTC P0125) being output. 

   PREPARATION: 

   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Turn the ignition switch to ON and turn the hand-held tester or the OBD II scan tool main switch ON.
   3. On the hand-held tester, select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.

   CHECK: 

   Read DTCs.

   RESULT: 

   DTC OUTPUT RESULT TABLE
   
   

   Display (DTC output)	Proceed To
   P0125	A
   P0125 and other DTCs	B

   HINT:

   If any other codes besides P0125 are output, perform troubleshooting for those DTCs first.

   • B: Go to DTC chart (See  DIAGNOSTIC TROUBLE CODE CHART   ). 
   • A: Go to next step. 
2. Check thermostat (See  INSPECTION  ). 
   • NG: Replace thermostat (See  REMOVAL  ). 
   • OK: Go to next step. 
3. Check cooling system. 

   CHECK: 

   Check for defects in the cooling system that might cause the system to be too cold, such as abnormal radiator fan operation or a modified cooling system.

   • NG: Repair or replace cooling system. 
   • OK: Replace engine coolant temperature sensor.