Inspection Procedure 15: Overheating


PROBABLE CAUSES



  • Insufficient or deteriorated engine coolant
  • Failed cooling fan
  • Failed fan clutch
  • Failed engine coolant temperature sensor
  • Failed thermostat
  • Failed water pump
  • Failed radiator core
  • Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III diagnosis code

Q. Diagnosis code set?
Inspection chart for diagnosis code (Refer to ).
Go to Step 2 .

STEP 2. Check cooling fan.

  • Check cooling fan (Refer to GROUP 14 - Cooling Fan - Inspection ).

Q. Is the check result normal?
Go to Step 3 .
Replace the cooling fan.

STEP 3. Check engine coolant
note If engine coolant level falls too early, check for leaky spots, and repair if necessary.

  • Check engine coolant (Refer to GROUP 14 - On-vehicle Service - Engine Coolant Leak Check ).

Q. Is the check result normal?
Go to Step 4 .
Replace or add engine coolant.

STEP 4. M.U.T.-III data list

  • Item 7: Engine coolant temperature sensor
OK:
    Engine cold state: At ambient temperature (atmospheric temperature) or equivalent.
    Engine hot state: At 80 - 120°C

Q. Is the check result normal?
Go to Step 5 .
Check engine coolant temperature sensor system (Refer to Code No. P0117: Engine Coolant Temperature Sensor Circuit Low Input , Code No. P0118: Engine Coolant Temperature sensor circuit High Input ).

STEP 5. Check thermostat.

  • Check thermostat (Refer to GROUP 14 - Thermostat - Thermostat Inspection ).

Q. Is the check result normal?
Go to Step 6 .
Replace the thermostat.

STEP 6. Check water pump.

  • Check water pump.

Q. Is the check result normal?
Replace the radiator.
Replace the water pump.