NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [L5]

NO.17 COOLING SYSTEM CONCERNS-OVERHEATING [L5]SM2444478

id0103a8802300

17	COOLING SYSTEM CONCERNS—OVERHEATING
DESCRIPTION	• Engine runs at higher than normal temperature/overheats.
POSSIBLE CAUSE	• Radiator hoses damage • Coolant leakage ― Leakage around heater unit ― Leakage at coolant hoses and/or radiator • Improper coolant level • Fans reverse rotation • Fuse malfunction • Coolant overflow system malfunction • Poor radiator condition • Improper or damaged radiator cap • Improper water/anti‐freeze mixture • PCM, climate control unit, instrument cluster or multi information display DTC is stored • Improper operation of A/C system ― Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal) ― Instrument cluster malfunction (does not receive A/C request signal from climate control unit or transmit it to PCM) ― Communication error between PCM and instrument cluster ― Communication error between instrument cluster and climate control unit • Improper operation of cooling fan control system • Improper tension of drive belt • Thermostat malfunction

COOLING SYSTEM CONCERNS—OVERHEATING

DESCRIPTION

• Engine runs at higher than normal temperature/overheats.

POSSIBLE CAUSE

• Radiator hoses damage

• Coolant leakage

― Leakage around heater unit

― Leakage at coolant hoses and/or radiator

• Improper coolant level

• Fans reverse rotation

• Fuse malfunction

• Coolant overflow system malfunction

• Poor radiator condition

• Improper or damaged radiator cap

• Improper water/anti‐freeze mixture

• PCM, climate control unit, instrument cluster or multi information display DTC is stored

• Improper operation of A/C system

― Climate control unit malfunction (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal)

― Instrument cluster malfunction (does not receive A/C request signal from climate control unit or transmit it to PCM)

― Communication error between PCM and instrument cluster

― Communication error between instrument cluster and climate control unit

• Improper operation of cooling fan control system

• Improper tension of drive belt

• Thermostat malfunction

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	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	Perform the PCM, climate control unit, instrument cluster and multi information display DTC inspection using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L5].) (See DTC DISPLAY [FULL-AUTO AIR CONDITIONER].) (See DTC INSPECTION [INSTRUMENT CLUSTER].) (See DTC INSPECTION [MULTI INFORMATION DISPLAY].) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE [L5].) (See DTC TABLE [FULL-AUTO AIR CONDITIONER].) (See DTC TABLE [INSTRUMENT CLUSTER].) (See DTC TABLE [MULTI INFORMATION DISPLAY].)
2		No	Go to the next step.
3	Start the engine and idle it. Turn the A/C switch on and set the blower fan to any speed. Does the magnetic clutch engage?	Yes	Go to Step 8.
3		No	Inspect the following: • Refrigerant charging amount • Open circuit in the wiring harness between the A/C relay and PCM terminal 1I • Seized A/C magnetic clutch • A/C magnetic clutch Repair or replace the malfunctioning part according to the inspection results. • If all items are normal: ― Go to the next step.
4	Access the PCM PID AC_REQ using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L5].) Start the engine and idle it. Monitor the AC_REQ PID while turning on and off the air conditioner by switching the control panel. Does the AC_REQ PID change according to air control panel switching? (See PCM INSPECTION [L5].)	Yes	Go to Step 8.
4		No	Go to the next step.
5	Verify the multi information display indication of A/C system while turning on and off the air conditioner by switching the control panel. Does the multi information display indicate properly?	Yes	Replace the instrument cluster (instrument cluster does not receive A/C request signal from climate control unit or transmit it to PCM). (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
5		No	Go to the next step.
6	Inspect the multi information display. (See MULTI INFORMATION DISPLAY INPUT/OUTPUT CHECK MODE.) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
6		No	Go to the next step.
7	Access the climate control unit PIDs EVAP_TEMP and AC_PRES using the M-MDS. (See PID/DATA MONITOR DISPLAY [FULL-AUTO AIR CONDITIONER].) Monitor the EVAP_TEMP and AC_PRES PIDs while turning on and off the air conditioner by switching the control panel. Is the PIDs normal? (See PID/DATA MONITOR TABLE [FULL-AUTO AIR CONDITIONER].)	Yes	Replace the climate control unit (A/C switch malfunction or climate control unit does not determine A/C request or transmit the A/C request signal.). (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
7		No	Repair or replace the malfunctioning part according to the inspection results.
8	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION [L5].) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		No	Go to the next step.
9	Inspect the drive belt. (See DRIVE BELT INSPECTION [L5].) Is there any malfunction?	Yes	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION [L5].)
9		No	Go to the next step.
10	Inspect the leakage around the heater unit in the passenger compartment. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
10		No	Go to the next step.
11	Inspect the leakage at the coolant hoses and/or radiator. Is there any leakage?	Yes	Repair or replace the malfunctioning part according to the inspection results.
11		No	Go to the next step.
12	Cool down the engine. Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION [L5].) (See THERMOSTAT INSPECTION [L5].) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION [L5].)
12		No	Install the thermostat, then go to the next step. (See THERMOSTAT REMOVAL/INSTALLATION [L5].)
13	Access the PCM PID ECT using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [L5].) Inspect for both ECT PID and temperature gauge readings. Does the ECT PID accord with temperature gauge readings?	Yes	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.
13		No	If the temperature gauge on instrument cluster indicates normal but the ECT PID is not same as temperature gauge reading: • Inspect the ECT sensor. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [L5].) • Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION [L5].) If the temperature gauge on instrument cluster indicates overheating but the ECT PID is normal: • Inspect the instrument cluster. (See INSTRUMENT CLUSTER INSPECTION.) • Replace the instrument cluster, if necessary. (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION.)
14	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [L5].) • If the malfunction remains, inspect the related Service 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.