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Home >> Mazda >> 2018 >> CX-9 Touring, AWD >> Repair and Diagnosis >> Engine Performance >> System >> Symptom Troubleshooting - Engine Control >> NO. 24 A/C Is Always On Or A/C Compressor Runs Continuously >> Diagnostic Procedure

Diagnostic Procedure

NO. 24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY (SKYACTIV-G 2.5T) DIAGNOSTIC PROCEDURE

STEP INSPECTION RESULTS ACTION
1 VERIFY PCM, INSTRUMENT CLUSTER AND CLIMATE CONTROL UNIT DTC Yes Go to the applicable DTC inspection. (See DTC TABLE [PCM (SKYACTIV-G 2.5T)] .)
(See DTC TABLE [INSTRUMENT CLUSTER] .)
(See DTC TABLE [CLIMATE CONTROL UNIT (FULL-AUTO AIR CONDITIONER)] .)
No Go to the next step.
2 DETERMINE IF MALFUNCTION CAUSE IS MAGNETIC CLUTCH OR OTHER
  • 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.
No Go to the next step.
3 INSPECT IF MALFUNCTION CAUSE ISMAGNETIC CLUTCH POWER SUPPLY CIRCUIT OR MAGNETIC CLUTCH
  • A/C relay is removed.
  • Switch the ignition off.
  • Disconnect the magnetic clutch connector.
  • Start the engine and idle it.
  • Does the magnetic clutch disengage?
Yes Inspect for a 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.
No Go to the next step.
4 INSPECT MAGNETIC CLUTCH CLEARANCE Yes Inspect the magnetic clutch to see if it is stuck.
(See MAGNETIC CLUTCH INSPECTION .)
Replace the magnetic clutch if necessary.
(See MAGNETIC CLUTCH DISASSEMBLY/ASSEMBLY .)
NO Adjust the magnetic clutch clearance.
(See MAGNETIC CLUTCH ADJUSTMENT .)
5 DETERMINE IF MALFUNCTION CAUSE IS A/C RELAY CONTROL SIGNAL OR A/C REQUEST SIGNAL
  • Access the PCM PID ACCS using the M-MDS. (See On-Board Diagnostic Test .)
  • 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 Climate control unit always transmits A/C request signal.
No Go to the next step.
6 INSPECT A/C RELAY Yes Replace the A/C relay.
No Inspect for a short to ground circuit between A/C relay terminal E and PCM terminal 2BB.
Repair or replace the wiring harness for a possible short to ground if necessary.
7 Verify the test results.
  • If normal, return to the diagnostic index to service any additional symptoms. (See Symptom Diagnostic Index .)
  • If a 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 .)