Inspection Procedure

HINT:

Read freeze frame data using the intelligent tester. Freeze frame data records 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. CHECK ANY OTHER DTCS OUTPUT (IN ADDITION TO DTC P0128) 
   1. Connect the intelligent tester to the DLC3.
   2. Turn the ignition switch ON.
   3. Turn the tester ON.
   4. Select the following menu items: DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES.
   5. Read DTCs.

   Result 

   RESULT
   
   

   Display (DTC Output)	Proceed To
   P0128	A
   P0128 and other DTCs	B

   HINT:

   If any DTCs other than P0128 are output, troubleshoot those DTCs first.

   B:  GO TO DTC CHART 

   A: GO to next step 

2. 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: GO to next step 

3. INSPECT THERMOSTAT 
   1. Remove the thermostat (See REMOVAL ).
   2. Measure the valve opening temperature of the thermostat.

      Standard value: 

      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: REPLACE ECM