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NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [WITH WU-TWC]

id0103008030c5

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

Diagnostic procedure

STEP | INSPECTION | RESULTS | ACTION
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1 | Connect the WDS or equivalent to the DLC-2. Retrieve any continuous memory, KOEO and KOER DTCs. (See KOEO/KOER SELF-TEST.) Are there any DTCs displayed? | Yes | DTC is displayed: Go to the appropriate DTC test.
No | No DTC is displayed: 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 | Inspect for the following: • A/C relay is stuck closed. • Short to ground circuit between the A/C relay and PCM terminal 1AL. If both items are normal, go to the next step.
No | Inspect if the circuit between the A/C relay and the magnetic clutch shorts to the battery power circuit. • If the circuit is normal, inspect the magnetic clutch for stuck engagement or clearance.
3 | Connect the WDS or equivalent to the DLC-2. Access the ACSW PID. Start the engine and turn the A/C switch on. Read the ACSW PID while disconnecting the refrigerant pressure switch connector. Note • The ACSW PID should read "off" when disconnecting the connector. If the ACSW PID reading remains on, a short to ground circuit may be present. Does the ACSW PID reading remain on? | Yes | Inspect for a short to ground circuit between the refrigerant pressure switch and the PCM terminal 1Q.
No | Go to the next step.
4 | Reconnect the refrigerant pressure switch connector. Read the ACSW PID while turning off the A/C switch. Note • The ACSW PID should read "off" when turning A/C switch off. If ACSW PID reading remains on, a short to ground circuit may be present. Does ACSW PID reading remain on? | Yes | Inspect the following: • Short to ground circuit between the A/C switch and A/C amplifier • Short to ground circuit between the A/C amplifier and refrigerant pressure switch
No | Inspect if the A/C switch is stuck closed.
5 | Verify the test results. • If normal, return to the diagnostic index to service any additional symptoms. • If the malfunction remains, inspect related Service information and perform repair or diagnosis. - If the vehicle is repaired, the troubleshooting is completed. - If the vehicle is not repaired or additional diagnostic information not available, replace the PCM.