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NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [L3]

BME010300000W26

24 | A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY.
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DESCRIPTION | A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE | • Stuck engagement A/C compressor magnetic clutch • A/C relay is stuck closed. • Short to GND between A/C switch and PCM • Short to GND circuit between A/C relay and PCM • A/C relay to magnetic clutch circuit shorted to battery power

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Connect WDS or equivalent to DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. Are there any DTCs displayed? | Yes | DTC is displayed: Go to appropriate DTC test.
No | No DTC is displayed: Go to next step.
2 | Start engine and run it at idle. Turn A/C switch on. Remove A/C relay. Does A/C magnetic clutch disengage? | Yes | Inspect for following: • A/C relay is stuck closed. • Short to GND circuit between A/C relay and PCM terminal 4O. If both items okay, go to next step.
No | Inspect if circuit between A/C relay and magnetic clutch shorts to battery power circuit. If circuit is okay, inspect magnetic clutch stuck engagement or clearance.
3 | Connect WDS or equivalent to DLC-2. Access ACSW PID. Start engine and turn A/C switch on. Read ACSW PID while disconnecting refrigerant pressure switch connector.

  Note

  • ACSW PID should read OFF when disconnecting connector. If ACSW PID reading remains ON, short to GND circuit may be present.
Does ACSW PID reading remain ON?

Yes
Inspect for short to GND circuit between refrigerant pressure switch and PCM terminal 1AC.
No | Go to next step.
4 | Reconnect refrigerant pressure switch connector. Read ACSW PID while turning off A/C switch.

  Note

  • ACSW PID should read OFF when turning A/C switch off. If ACSW PID reading remains ON, short to GND circuit may be present.
Does ACSW PID reading remain ON?

Yes
Inspect following:
• Short to GND circuit between A/C switch and A/C amplifier
• Short to GND circuit between A/C amplifier and refrigerant pressure switch
No | Inspect for stuck closed A/C switch.
5 | Verify test results. • If okay, return to diagnostic index to service any additional symptoms. • If malfunction remains, replace PCM.