NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR 1.3, MZR 1.5]

id0103d7803000

24

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

DESCRIPTION

•  The 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 terminal E and PCM terminal 1AN

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

•  Short to ground in wiring harness between climate control unit terminal R and PCM terminal 1AO (full-auto air conditioner)

•  Short to ground in wiring harness between climate control unit terminal K and PCM terminal 1AO (manual air conditioner)

•  PCM malfunction

24	A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION	• The 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 terminal E and PCM terminal 1AN • A/C relay to magnetic clutch circuit short to battery power • Short to ground in wiring harness between climate control unit terminal R and PCM terminal 1AO (full-auto air conditioner) • Short to ground in wiring harness between climate control unit terminal K and PCM terminal 1AO (manual air conditioner) • PCM malfunction

Diagnostic procedure

STEP	INSPECTION	RESULTS	ACTION
1	VERIFY PCM DTC • Retrieve any continuous memory DTCs using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.3, MZR 1.5].) • Are there any continuous memory DTCs displayed?	Yes	Continuous memory DTC is displayed: • Go to the applicable DTC inspection. (See DTC TABLE [MZR 1.3, MZR 1.5].) Communication error message is displayed: • Inspect the following: ― Open circuit in wiring harness between main relay terminal B and PCM terminal 1AJ ― Open circuit in wiring harness between main relay terminal D and PCM terminals 1BB ― Open circuit in wiring harness between main relay terminal D and PCM terminals 1BG (ATX) ― Main relay is stuck open. ― Open or poor PCM ground circuit (PCM terminals 2AZ, 2BA, 2BB, 2BD and 2BH) ― Poor connection of vehicle body ground • Repair or replace the malfunctioning part according to the inspection results.
1		No	Go to the next step.
2	DETERMINE IF MALFUNCTION CAUSE IS A/C COMPRESSOR OR A/C COMPRESSOR DRIVE SIGNAL • Start the engine and idle it. • Turn the A/C switch on. • Remove the A/C relay. • Does the magnetic clutch disengage?	Yes	Go to Step 5.
2		No	Go to the next step.
3	DETERMINE IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH POWER SUPPLY OR MAGNETIC CLUTCH • Turn the ignition switch off. • Disconnect the magnetic clutch connector. • Start the engine and idle it. • Does the magnetic clutch disengage?	Yes	Inspect for short to power supply between magnetic clutch terminal A and A/C relay terminal D. Repair or replace the wiring harness for a possible short to power supply if necessary.
3		No	Go to the next step.
4	INSPECT MAGNETIC CLUTCH CLEARANCE • Verify the magnetic clutch clearance. (See MAGNETIC CLUTCH ADJUSTMENT [FULL-AUTO AIR CONDITIONER].) (See MAGNETIC CLUTCH ADJUSTMENT [MANUAL AIR CONDITIONER].) • Is there any malfunction?	Yes	Adjust the magnetic clutch clearance. (See MAGNETIC CLUTCH ADJUSTMENT [FULL-AUTO AIR CONDITIONER].) (See MAGNETIC CLUTCH ADJUSTMENT [MANUAL AIR CONDITIONER].)
4		No	Inspect the magnetic clutch to see if it is 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].)
5	DETERMINE IF MALFUNCTION CAUSE IS A/C REQUEST SIGNAL OR MAGNETIC CLUTCH CONTROL CIRCUIT • Access the AC_REQ PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.3, MZR 1.5].) • Monitor the AC_REQ PID 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 REFRIGERANT PRESSURE SWITCH • 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 R and PCM terminal 1AO. (full-auto air conditioner) Inspect for short to ground in wiring harness between climate control unit terminal K and PCM terminal 1AO. (manual air conditioner) • If there is any malfunction: ― Repair or replace the wiring harness for a possible short to ground. • 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 A/C RELAY • 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 1AN. 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 1.3, MZR 1.5].) • 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, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.3, MZR 1.5].)