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


BHE010300103W26

24

A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY.

DESCRIPTION

The 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

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 applicable DTC inspection.
(See DTC TABLE.)
No

No DTC is displayed:

Go to the next step.
2
Start the engine and run it at idle.
Turn the A/C switch on.
Remove the A/C relay.
Does the A/C magnetic clutch disengage?
Yes
Inspect for the following:
• The A/C relay is stuck closed.
• Short to GND circuit between the A/C relay and PCM terminal 5AA.
If both items 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 indicate that it is off when disconnecting the connector. If the ACSW PID remains on, a short to GND circuit may be present.
Does the ACSW PID remain on?
Yes
Inspect for short to GND circuit between refrigerant pressure switch and PCM terminal 4W.
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 indicate that it is off when turning the A/C switch off. If the ACSW PID remains on, a short to GND circuit may be present.
Does the ACSW PID remain on?
Yes
Inspect the 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 normal, return to the diagnostic index to service any additional symptoms.
• If the malfunction remains, inspect the related Service Information and perform the repair or diagnosis.