Inspection Procedure 18: Overheating

COMMENTS ON TROUBLE SYMPTOM

The failure could possibly be caused by the failed engine cooling system, defective cooling fan system, faulty engine coolant temperature sensor and so on.

PROBABLE CAUSES

Insufficient amount or deteriorated quality of engine coolant
Failed cooling fan system
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. Is the diagnosis code stored?

	Inspection chart for diagnosis code (Refer to ).

	Go to Step 2.

STEP 2. Check engine coolant.

note

When the engine coolant level is too low, check for any section that cases leakage 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 3.

	Replace or fill the engine coolant.

STEP 3. M.U.T.-III actuator test

Refer to Actuator Test Reference Table .

Item 12: Radiator fan (high)
Item 13: Radiator fan (low)

Q. Are the check results normal?

	Go to Step 4.

	Check Inspection Procedure - Fan Control Relay System (Refer to <CVT (Except vehicles for Thailand and Malaysia)>, <M/T, CVT (Vehicles for Thailand and Malaysia)>).

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

Item 6: 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. Check code No. P0117: engine coolant temperature sensor circuit low input (Refer to ). Check code No. P0118: engine coolant temperature sensor circuit high input (Refer to ).

STEP 5. Check thermostat.

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

Q. Is the check result normal?

	Go to Step 6.

	Replace the thermostat.

STEP 6. Check water pump.

Check water pump (Refer to GROUP 14 - On-vehicle Service - Water Pump Coolant Leak Check ).

Q. Is the check result normal?

	Replace the radiator.

	Replace the water pump.