Diagnostic Procedure

NO. 17 COOLING SYSTEM CONCERNS-OVERHEATING DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	INSPECT RELATED PART CONDITION Inspect the following: Collapsed or restricted radiator hoses Coolant leakage Engine coolant level Fan rotational direction Fuses Overflow system Radiator condition Radiator pressure cap Water and anti-freeze mixture Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results. Repeat Step 1.
1		No	Go to the next step.
2	VERIFY PCM DTC Perform the PCM DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
2		No	Go to the next step.
3	VERIFY PRESENT MALFUNCTION DTC Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .)
3		No	Go to the next step.
4	DETERMINE IF MALFUNCTION CAUSE IS A/C SYSTEM OR OTHER Start the engine and run it at idle speed. Turn the A/C switch off. Does the A/C compressor disengaged?	Yes	Go to the next step.
4		No	Go to the symptom troubleshooting "NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY". (See NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY .)
5	INSPECT COOLING FAN CONTROL SYSTEM OPERATION Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Does the cooling fan control system operate properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	INSPECT DRIVE BELT Inspect the drive belt. (See DRIVE BELT INSPECTION .) Is there any malfunction?	Yes	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION .)
6		No	Go to the next step.
7	INSPECT COOLANT LEAKAGE AT HEATER UNIT Inspect for leakage around heater unit in passenger compartment. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
7		No	Go to the next step.
8	INSPECT COOLANT LEAKAGE AT COOLING SYSTEM PART Inspect for leakage at coolant hoses and/or radiator. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	INSPECT ECT SENSOR SIGNAL Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Compare the ECT PID and low engine coolant temperature indicator light and high engine coolant temperature warning light operation. Is the ECT PID value same as indicator/warning light readings?	Yes	Go to the next step.
9		No	Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION .) If there is any malfunction: Replace the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION .) If there is no malfunction: Replace the instrument cluster. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION .)
10	INSPECT THERMOSTAT Cool down the engine. Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION .) Inspect the thermostat operation. (See THERMOSTAT INSPECTION .) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION .)
10		No	Reinstall the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION .) The engine coolant temperature and thermostat are normal. Inspect the engine block for leakage or blockage. Repair or replace the malfunctioning part according to the inspection results.
11	Verify test results. If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX .) If the malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform repair or diagnosis. If the vehicle is repaired, troubleshooting is completed. If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if a later calibration is available. Retest.