Diagnostic Procedure

NO. 23 A/C DOES NOT WORK SUFFICIENTLY DIAGNOSTIC PROCEDURE

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM, INSTRUMENT CLUSTER AND CLIMATE CONTROL UNIT DTC Retrieve the PCM, instrument cluster and climate control unit DTCs. (See ON-BOARD DIAGNOSTIC TEST .) (See DTC INSPECTION [INSTRUMENT CLUSTER] .) (See DTC DISPLAY [FULL-AUTO AIR CONDITIONER] .) Are any DTCs present?	Yes	Go to the applicable DTC inspection. (See DTC TABLE .) (See DTC TABLE [INSTRUMENT CLUSTER] .) (See DTC TABLE [FULL-AUTO AIR CONDITIONER] .)
1		No	Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR MAGNET CLUTCH DRIVE SIGNAL Access the PCM PID ACCS using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Start the engine and idle it. Turn the ACCS PID to ON from OFF using the M-MDS simulation function. Is the magnetic clutch engaged?	Yes	Go to the next step.
2		No	Go to Step 9.
3	DETERMINE IF MALFUNCTION CAUSE IS REFRIGERANT PRESSURE SENSOR OR OTHER Access the PCM PID AC_REQ using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Monitor the AC_REQ PID while turning on and off the air conditioner by switching the control panel. Is the AC_REQ PID normal? (See PCM INSPECTION .)	Yes	Inspect for seizure of A/C compressor magnetic clutch. Repair or replace malfunctioning part according to inspection result.
3		No	Go to the next step.
4	INSPECT REFRIGERANT PRESSURE SENSOR Inspect the refrigerant pressure sensor. (See REFRIGERANT PRESSURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER] .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
4		No	Go to the next step.
5	DETERMINE IF MALFUNCTION CAUSE IS EVAPORATOR TEMPERATURE SENSOR OR OTHER Access the climate control unit PID EVAP_TEMP using the M-MDS. (See PID/DATA MONITOR DISPLAY [FULL-AUTO AIR CONDITIONER] .) Monitor the EVAP_TEMP PID while turning on and off the air conditioner by switching the control panel. Is the PID value normal? (See PID/DATA MONITOR TABLE [FULL-AUTO AIR CONDITIONER] .)	Yes	Go to Step 7.
5		No	Go to the next step.
6	INSPECT EVAPORATOR TEMPERATURE SENSOR Inspect the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR INSPECTION [FULL-AUTO AIR CONDITIONER] .) Is there any malfunction?	Yes	Replace the evaporator temperature sensor. (See EVAPORATOR TEMPERATURE SENSOR REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
6		No	Inspect for open or short circuit between evaporator temperature sensor and climate control unit. Repair or replace the malfunctioning part according to the inspection results.
7	DETERMINE IF MALFUNCTION CAUSE IS INSTRUMENT CLUSTER OR OTHER Verify the information display indication of A/C system while turning on and off the air conditioner by switching the control panel. Does the information display indicate properly?	Yes	Replace the instrument cluster. (Instrument cluster does not receive the A/C request signal from climate control unit or transmit it to PCM.) (See INSTRUMENT CLUSTER REMOVAL/INSTALLATION .)
7		No	Go to the next step.
8	DETERMINE IF MALFUNCTION CAUSE IS INFORMATION DISPLAY OR CLIMATE CONTROL UNIT Inspect the information display. (See INFORMATION DISPLAY INSPECTION .) Is there any malfunction?	Yes	Repair or replace the malfunctioning part according to the inspection results.
8		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/INSTALLATION [FULL-AUTO AIR CONDITIONER] .)
9	DETERMINE IF MALFUNCTION CAUSE IS A/C CONTROL SIGNAL OR MAGNETIC CLUTCH Start the engine and idle it. Access the PCM PID ACCS using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST .) Turn the ACCS PID to ON from OFF using the M-MDS simulation function. Measure the voltage at the magnetic clutch terminal A (wiring harness-side). Is the voltage 10.5 V or more?	Yes	Go to the next step.
9		No	Go to Step 11.
10	INSPECT MAGNETIC CLUTCH GROUND CIRCUIT FOR OPEN CIRCUIT Inspect for continuity between magnetic clutch terminal A (wiring harness-side) and body ground. Is there continuity?	Yes	Go to the next step.
10		No	Repair or replace for open circuit and/or poor contact ground points.
11	INSPECT A/C RELAY Inspect the A/C relay. (See RELAY INSPECTION .) Is there any malfunction?	Yes	Replace the A/C relay. (See RELAY LOCATION .)
11		No	Go to the next step.
12	INSPECT A/C RELAY CONTROL CIRCUIT FOR OPEN CIRCUIT Switch the ignition to off. Remove the A/C relay. (See RELAY LOCATION .) Disconnect the PCM connector. Inspect for continuity between A/C relay and PCM terminal 1I (wiring harness-side). Is there continuity?	Yes	Inspect the open circuit in following: Between ignition switch (IG2) and A/C relay Between battery positive terminal and A/C relay Between A/C relay and magnetic clutch Repair or replace the malfunctioning part according to the inspection results.
12		No	Repair or replace the suspected wiring harness.
13	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.