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.

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

1
Connect the WDS or equivalent to the DLC-2.
Retrieve any continuous memory, KOEO and KOER DTCs.
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.