NO.26 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR-CD 2.2]

id0103f3822400

26

A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY

DESCRIPTION

•  A/C compressor magnetic clutch does not disengage.

POSSIBLE CAUSE

•  A/C compressor magnetic clutch stuck engagement

•  A/C relay is stuck closed

•  Improper A/C compressor magnetic clutch clearance

•  Short to ground in wiring harness between A/C relay and PCM

•  A/C relay to magnetic clutch circuit short to battery power

•  Short to ground in wiring harness between climate control unit and PCM terminal 1AF

26	A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION	• A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE	• A/C compressor magnetic clutch stuck engagement • A/C relay is stuck closed • Improper A/C compressor magnetic clutch clearance • Short to ground in wiring harness between A/C relay and PCM • A/C relay to magnetic clutch circuit short to battery power • Short to ground in wiring harness between climate control unit and PCM terminal 1AF

Diagnostic Procedure

STEP	INSPECTION	RESULTS	ACTION
1	Perform the KOEO or KOER self test. (See KOEO/KOER SELF TEST [MZR-CD 2.2].) Retrieve the PCM, instrument cluster and climate control unit DTCs. (See DTC INSPECTION [INSTRUMENT CLUSTER].) (See DTC DISPLAY [WATER HEATER SYSTEM].) (See DTC DISPLAY [FULL-AUTO AIR CONDITIONER].) Are any DTCs displayed?	Yes	DTC is displayed: • Go to the applicable DTC inspection. (See DTC TABLE [MZR-CD 2.2].) (See DTC TABLE [INSTRUMENT CLUSTER].) (See DTC TABLE [WATER HEATER SYSTEM].) (See DTC TABLE [FULL-AUTO AIR CONDITIONER].)
1		No	Go to the next step.
2	Start the engine and run it at idle. Turn the A/C switch on. Remove the A/C relay. Does the A/C magnetic clutch disengage?	Yes	Go to Step 5.
2		No	Go to the next step.
3	Switch the ignition to off. Disconnect the magnetic clutch connector. Start the engine and idle it. Does the magnetic clutch disengage?	Yes	Inspect for short to power supply circuit between magnetic clutch terminal A and A/C relay terminal C. Repair or replace the wiring harness for a possible short to power supply if necessary.
3		No	Go to the next step.
4	Verify the magnetic clutch clearance. (See MAGNETIC CLUTCH ADJUSTMENT [FULL-AUTO AIR CONDITIONER].) (See MAGNETIC CLUTCH ADJUSTMENT [MANUAL AIR CONDITIONER].) Is the magnetic clutch clearance normal?	Yes	Inspect the magnetic clutch for stuck. (See MAGNETIC CLUTCH INSPECTION [FULL-AUTO AIR CONDITIONER].) (See MAGNETIC CLUTCH INSPECTION [MANUAL AIR CONDITIONER].) Replace the magnetic clutch if necessary. (See MAGNETIC CLUTCH DISASSEMBLY/ASSEMBLY [FULL-AUTO AIR CONDITIONER].) (See MAGNETIC CLUTCH DISASSEMBLY/ASSEMBLY [MANUAL AIR CONDITIONER].)
4		No	Adjust the magnetic clutch clearance. (See MAGNETIC CLUTCH ADJUSTMENT [FULL-AUTO AIR CONDITIONER].) (See MAGNETIC CLUTCH ADJUSTMENT [MANUAL AIR CONDITIONER].)
5	Access the PCM PID AC_REQ using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR-CD 2.2].) Monitor the PCM PID AC_REQ while turning on and off the air conditioner by switching the control panel. Is the AC_REQ PID always ON?	Yes	Go to the next step.
5		No	Go to Step 7.
6	Inspect the refrigerant pressure switch. (See REFRIGERANT PRESSURE SWITCH INSPECTION [FULL-AUTO AIR CONDITIONER].) (See REFRIGERANT PRESSURE SWITCH INSPECTION [MANUAL AIR CONDITIONER].) Is there any malfunction?	Yes	Replace the refrigerant pressure switch. (See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].) (See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)
6		No	Inspect for short to ground in wiring harness between climate control unit terminal 1U (Full-auto air conditioner)/1L (Manual air conditioner) and PCM terminal 1AF. • If there is no malfunction: ― Replace the climate control unit. (A/C request signal always ON) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)
7	Inspect the A/C relay. (See RELAY INSPECTION.) Is there any malfunction?	Yes	Replace the A/C relay.
7		No	Inspect for short to ground in wiring harness between A/C relay terminal E and PCM terminal 1BX. Repair or replace the wiring harness for a possible short to ground if necessary.
8	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR-CD 2.2].) • 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.