Inspection Procedure

HINT:

Read freeze frame data using the Techstream. 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 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 Techstream to the DLC3.
   2. Turn the ignition switch to ON.
   3. Turn the Techstream on.
   4. Enter the following menus: Powertrain/Engine/Trouble Codes.
   5. Read the DTCs.

      Result 

      RESULT CHART
      
      

      Result	Proceed to
      DTC P0128 is output	A
      DTC P0128 and other DTCs are output	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 cooling 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. Check 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  (See REMOVAL )

      OK: REPLACE ECM  (See REMOVAL )