No. 24 A/C Is Always On Or A/C Compressor Runs Continuously

POSSIBLE CAUSE

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

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.
(See DTC TABLE ).

No DTC is displayed:
Go to the next step.

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 1AN.

If both items normal, go to the next step.

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.

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⁽¹⁾, 1AP⁽²⁾, 1AU⁽³⁾.

Go to the next step.

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

Inspect whether A/C switch is stuck closed.

Verify test results.
- If normal, return to diagnostic index to service any additional symptoms.
  (See ENGINE SYMPTOM TROUBLESHOOTING ).
- If malfunction remains, inspect related Service Bulletins and/or On-line Repair 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 ).

⁽¹⁾	California emission regulation applicable model

⁽²⁾	Except for California emission regulation applicable model with LF engine ATX

⁽³⁾	Except for California emission regulation applicable model with LF engine MTX and L3 engine