Inspection Procedure

HINT:

Read freeze frame data using the hand-held tester or the OBD II scan tool. Freeze frame data records the engine conditions when a malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the air-fuel ratio was lean or rich, etc. at the time of the malfunction.

1. CHECK COOLING SYSTEM 
   1. Check that there is a defect in the cooling system which causes overcool, such as abnormal radiator fan operation, modified cooling system and so on.
   • NG : REPAIR OR REPLACE COOLING SYSTEM 
   • OK : Go to next step 
2. INSPECT THERMOSTAT (See  INSPECTION  ) 
   • NG : REPLACE THERMOSTAT (See  REPLACEMENT  ) 
   • OK : Go to next step 
3. CHECK OTHER DTC OUTPUT (IN ADDITION TO DTC P0128) 
   1. Connect the hand-held tester or the OBD II scan tool to the DLC3.
   2. Turn the ignition switch ON and push the hand-held tester or the OBD II scan tool main switch ON.
   3. Select the item "DIAGNOSIS / ENHANCED OBD II / DTC INFO / CURRENT CODES".
   4. Read the DTCs.

      Result: 

      RESULT REFERENCE
      
      

      Display (DTC output)	Proceed to
      P0128	A
      P0128 and other DTCs	B

   HINT:

   If any other codes besides P0128 is output, perform the troubleshooting for those DTCs first.

   • B : GO TO RELEVANT  DIAGNOSTIC TROUBLE CODE CHART  
   • A : REPLACE ECM (See  REPLACEMENT  )