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 .) (See DTC DISPLAY .) (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 .) (See DTC Table.) (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 11.
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 .) 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 .)	Yes	Go to Step 11.
4		No	Manual air conditioner: Go to Step 8. Full-auto air conditioner: 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 .) 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 .)	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	Remove the climate control unit. (See CLIMATE CONTROL UNIT REMOVAL [MANUAL AIR CONDITIONER] .) Reconnect the climate control unit connector. Start the engine and idle it. Measure the voltage at the climate control unit terminal J while turning on and off the air conditioner by switching the control panel. Is the voltage change in specified according to air control panel switching? (See PCM INSPECTION .)	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 .)
8		No	Go to the next step.
9	Inspect for following part and related harness: Refrigerant pressure sensor (climate control unit terminal N) Evaporator temperature sensor (climate control unit terminal I) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
9		No	Go to the next step.
10	Inspect for open or short circuit between climate control unit terminal J (wiring harness-side) and BCM terminal 3L (wiring harness-side). Is there any malfunction?	Yes	Repair or replace the suspected wiring harness.
10		No	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 [MANUAL AIR CONDITIONER] .) (See CLIMATE CONTROL UNIT INSTALLATION [MANUAL AIR CONDITIONER] .)
11	Perform the Cooling Fan Control System Inspection. (See ENGINE CONTROL SYSTEM OPERATION INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
11		No	Go to the next step.
12	Inspect the drive belt. (See DRIVE BELT INSPECTION .) Is there any malfunction?	Yes	Replace the drive belt. (See DRIVE BELT REMOVAL/INSTALLATION .)
12		No	Go to the next step.
13	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.
13		No	Go to the next step.
14	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.
14		No	Go to the next step.
15	Cool down the engine. Remove the thermostat and inspect operation. (See THERMOSTAT REMOVAL/INSTALLATION .) (See THERMOSTAT INSPECTION .) Is there any malfunction?	Yes	Replace the thermostat. (See THERMOSTAT REMOVAL/INSTALLATION .)
15		No	Install the thermostat, then go to the next step. (See THERMOSTAT REMOVAL/INSTALLATION .)
16	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 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.
16		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 .) Replace the ECT sensor, if necessary. (See ENGINE COOLANT TEMPERATURE (ECT) SENSOR REMOVAL/INSTALLATION .) 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 .)
17	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.