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 NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [L8, LF, L3]

NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [L8, LF, L3]

id0103a1803000

24

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

DESCRIPTION

A/C compressor magnetic clutch does not disengage.

POSSIBLE CAUSE

• A/C compressor magnetic clutch engagement is stuck.
• A/C relay is stuck closed.
• Short to GND in wiring harness between A/C switch and PCM
• Short to GND in wiring harness between A/C relay and PCM
• Short circuit to battery power in A/C relay to magnetic clutch

Diagnostic procedure

STEP

INSPECTION

RESULTS

ACTION

1
Connect the WDS or equivalent to the DLC-2.
Turn the ignition switch to the ON position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?
Yes

DTC is displayed:

Go to the appropriate DTC inspection.
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 GND in wiring harness between A/C relay and PCM terminal 1I.
If both items normal, go to the next step.
No
Inspect if circuit between the A/C relay and magnetic clutch shorts to battery power circuit.
If the circuit is normal, inspect the magnetic clutch for stuck engagement or clearance.
3
Disconnect refrigerant pressure switch connector.
Start the engine and turn A/C switch on.
Note
• A/C should not work when disconnecting connector. If A/C remains working, short to GND circuit may be present.
Does the A/C remain working?
Yes
Inspect for short to GND in wiring harness between refrigerant pressure switch and PCM terminal 1AU.
No
Go to the next step.
4
Reconnect refrigerant pressure switch connector.
Turn off A/C switch.
Note
• A/C should not work when turning A/C switch off. If A/C remains working, short to GND circuit may be present.
Does A/C remain working?
Yes
Inspect following:
• Short to GND in wiring harness between A/C switch and A/C amplifier
• Short to GND circuit between A/C amplifier and refrigerant pressure switch
No
Inspect whether A/C switch is stuck closed.
5
• Verify test results.
- If normal, return to diagnostic index to service any additional symptoms.
(See ENGINE SYMPTOM TROUBLESHOOTING [L8, LF, L3].)
- If malfunction remains, inspect related Service Information and perform repair or diagnosis.
• If vehicle is repaired, troubleshooting completed.
• If vehicle is not repaired or additional diagnostic information is not available, replace the PCM.
(See PCM REMOVAL/INSTALLATION [L8, LF, L3].)