NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [L5]SM2444484
NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [L5]

id0103a8803000

24

A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION
• A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE
• PCM, instrument cluster or climate control unit DTC is stored
• Short to power supply in wiring harness between A/C relay and magnetic clutch
• A/C compressor magnetic clutch engagement is stuck
• A/C relay malfunction
• Short to ground in wiring harness between A/C relay and PCM
• Climate control unit malfunction

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION
1
Retrieve the PCM, BCM, instrument cluster and climate control unit DTCs.
(See ON-BOARD DIAGNOSTIC TEST [L5].)
(See DTC INSPECTION [BCM].)
(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 [L5].)
(See DTC TABLE [BCM].)
(See DTC TABLE [INSTRUMENT CLUSTER].)
(See DTC TABLE [FULL-AUTO AIR CONDITIONER].)
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 5.
No
Go to the next step.
3
Turn the ignition switch off.
Disconnect the A/C compressor connector.
Start the engine and idle it.
Does the A/C magnetic clutch disengage?
Yes
Inspect for short to power supply in wiring harness between A/C relay terminal 5 and A/C compressor connector.
No
Go to the next step.
4
Verify that the A/C magnetic clutch clearance.
(See MAGNETIC CLUTCH ADJUSTMENT [FULL-AUTO AIR CONDITIONER].)
Is the magnetic clutch clearance normal?
Yes
Inspect the A/C magnetic clutch for stuck.
(See MAGNETIC CLUTCH INSPECTION [FULL-AUTO AIR CONDITIONER].)
Repair or replace the malfunctioning part according to the inspection results.
(See MAGNETIC CLUTCH DISASSEMBLY/ASSEMBLY [FULL-AUTO AIR CONDITIONER].)
No
Adjust the magnetic clutch clearance.
5
Access the AC_REQ PID using the M-MDS.
(See ON-BOARD DIAGNOSTIC TEST [L5].)
Monitor the AC_REQ PID while turning on and off the air conditioner by switching the control penal.
Is the AC_REQ PID always ON?
Yes
Replace the climate control unit (A/C request signal always ON).
(See CLIMATE CONTROL UNIT REMOVAL/INSTALLATION [FULL-AUTO AIR CONDITIONER].)
No
Go to the next step.
6
Inspect the A/C relay.
(See RELAY INSPECTION [L5].)
Is there any malfunction?
Yes
Replace the A/C relay.
No
Inspect for short to ground in wiring harness between PCM terminal 1I and A/C relay terminal 2.
Repair or replace the suspected wiring harness.
7
Verify test results.
• If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [L5].)
• 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.