NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR 1.6]

id0103f9803000

24

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

DESCRIPTION

•  The A/C compressor magnetic clutch does not disengage.

POSSIBLE CAUSE

•  Continuous memory DTC is stored

•  Short to power supply in wiring harness between A/C relay and magnetic clutch

•  A/C magnetic clutch engagement is stuck

•  A/C relay malfunction (stuck closed)

•  Communication error between instrument cluster and climate control unit (with full-auto air conditioner)

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

•  Short to ground circuit between instrument cluster terminal L and climate control unit terminal B (with 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	• Continuous memory DTC is stored • Short to power supply in wiring harness between A/C relay and magnetic clutch • A/C magnetic clutch engagement is stuck • A/C relay malfunction (stuck closed) • Communication error between instrument cluster and climate control unit (with full-auto air conditioner) • Short to ground in wiring harness between A/C relay and PCM • Short to ground circuit between instrument cluster terminal L and climate control unit terminal B (with manual air conditioner) • PCM malfunction

Diagnostic Procedure

STEP	INSPECTION	ACTION
1	Retrieve the PCM, instrument cluster, and climate control unit (with full-auto air conditioner) DTCs. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.6].) (See DTC INSPECTION [INSTRUMENT CLUSTER].) (See DTC DISPLAY [FULL-AUTO AIR CONDITIONER].) Are any DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [MZR 1.6].) (See DTC TABLE [INSTRUMENT CLUSTER].) (See DTC TABLE [FULL-AUTO AIR CONDITIONER].)
1		No	Go to the next step.
2	Start the engine and idle it. Turn the A/C switch on. Remove the A/C relay. Does the A/C magnetic clutch disengage?	Yes	Go to Step 4.
2		No	Go to the next step.
3	Switch the ignition off. A/C relay removed. Disconnect the A/C compressor connector. Switch the ignition ON (engine off). Measure the voltage at the magnetic clutch terminal A (wiring harness-side). Is the voltage B+?	Yes	Repair or replace the wiring harness for a possible short to power supply.
3		No	Replace the A/C compressor magnetic clutch.
4	Inspect the A/C relay. (See RELAY INSPECTION.) Is the A/C relay normal?	Yes	Go to the next step.
4		No	Replace the A/C relay.
5	Access the ACCS PID using the M-MDS. (See ON-BOARD DIAGNOSTIC TEST [MZR 1.6].) Start the engine and idle it. Monitor the PID ACCS while turning on and off the air conditioner using the switch on the control panel. Is the ACCS PID value always ON?	Yes	Full-auto air conditioner: • Replace the climate control unit. (A/C request signal always on.) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].) Manual air conditioner: • Go to the next step.
5		No	Inspect for short to ground in wiring harness between PCM terminal 1AT and A/C relay terminal E. Repair or replace the malfunctioning part according to the inspection results.
6	Switch the ignition off. Disconnect the instrument cluster and climate control unit connectors. Inspect for continuity the wiring harness between climate control unit terminal B (wiring harness-side) and body ground. Is there continuity?	Yes	Repair or replace the wiring harness for a possible short to ground.
6		No	Replace the climate control unit. (A/C request signal always on.) (See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [MANUAL AIR CONDITIONER].)
7	Verify the test results. • If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR 1.6].) • If malfunction remains, inspect related Service information perform repair or diagnosis. ― If vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZR 1.6].)