NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [ZY, Z6]

id0103b9803000

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 (for full-auto air conditioner)

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

•  Short to ground circuit between instrument cluster terminal 2I and climate control unit terminal 2P (16-pin) (for 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 (for full-auto air conditioner) • Short to ground in wiring harness between A/C relay and PCM • Short to ground circuit between instrument cluster terminal 2I and climate control unit terminal 2P (16-pin) (for manual air conditioner) • PCM malfunction

Diagnostic procedure

STEP	INSPECTION	ACTION
1	Connect the M-MDS to the DLC-2. Retrieve the PCM, instrument cluster, multi information display and climate control unit (for full-auto air conditioner) DTCs. (See ON-BOARD DIAGNOSTIC TEST [ZY, Z6].) (See DTC INSPECTION [INSTRUMENT CLUSTER].) (See DTC INSPECTION [INFORMATION DISPLAY/MULTI INFORMATION DISPLAY].) (See DTC DISPLAY [FULL-AUTO AIR CONDITIONER].) Are any DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [ZY, Z6].) (See DTC TABLE [INSTRUMENT CLUSTER].) (See DTC TABLE [INFORMATION DISPLAY/MULTI INFORMATION DISPLAY].) (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 to off. A/C relay removed. Disconnect the A/C compressor connector. Switch the ignition to ON (engine off). Measure the voltage between A/C compressor terminal B (wiring harness-side) and body ground. 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 [ZY, Z6].) Start the engine and idle it. Turn the A/C switch on and off with blower switch is on. Is the 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 1AN and A/C relay terminal E. Repair or replace the malfunctioning part according to the inspection results.
6	Switch the ignition to off. Disconnect the instrument cluster and climate control unit connectors. Inspect for continuity the wiring harness between climate control unit terminal 2P (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 [ZY, Z6].) • 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 [ZY, Z6].)