No. 17 Cooling System Concerns-Overheating

17	COOLING SYSTEM CONCERNS-OVERHEATING
DESCRIPTION	Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	Improper coolant level Coolant leakage (engine internal, turbocharger, external) Improper water/anti-freeze mixture Poor radiator condition Radiator hose damage Improper or damaged radiator pressure cap Coolant overflow system malfunction Fans reverse rotation Blown fuse PCM DTC is stored Improper operation of A/C system Excessive A/C system pressure Cooling fan inoperative Drive belt damage Improper drive belt tension Leakage coolant from heater unit in passenger compartment Leakage at coolant hoses and/or radiator Improper indication of low engine coolant temperature indicator light/high engine coolant warning light ECT sensor No. 1 malfunction Instrument cluster malfunction Thermostat malfunction

DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	Inspect for the following: Engine coolant level Coolant leakage (around heater unit in passenger compartment, coolant hoses and/or radiator). Water and anti-freeze mixture Radiator condition Collapsed or restricted radiator hoses Radiator pressure cap Coolant overflow system Fan rotational direction Fuses Is there any malfunction?	Yes	Service if necessary. Repeat this step.
1		No	Go to the next step.
2	Switch the ignition to ON. Retrieve any DTCs 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	Perform the KOEO or KOER self test using the M-MDS. (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	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	Perform 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	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION ). Does the cooling fan system operate properly?	Yes	Go to the next step.
5		No	Repair or replace the malfunctioning part according to the inspection results.
6	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 for leakage around heater unit in the passenger compartment. Is there any leakage?	Yes	Inspect the heater unit for leakage. Repair or replace the malfunctioning part according to the inspection results.
7		No	Go to the next step.
8	Inspect for leakage at the 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	Access the ECT PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST ). Inspect for both ECT PID and temperature gauge readings. Does the ECT PID value accord with the high engine coolant temperature warning readings?	Yes	Go to the next step.
9		No	Inspect the ECT sensor No. 1. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR INSPECTION ). If there is any malfunction: Replace the ECT sensor No. 1. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION ). If there is no malfunction: Replace the instrument cluster. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION ).
10	Cool down the engine. Remove the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION ). Inspect the thermostat. (See THERMOSTAT INSPECTION ). Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION ).
10		No	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. If a malfunction remains, inspect the related Service Bulletins and/or On-line Repair Information and perform the 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.