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

id0103f2803000

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

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.)
1		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.
2		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 AC_REQ PID. Start the engine and turn the A/C switch on. Read the AC_REQ PID while disconnecting the refrigerant pressure switch connector. Note • The AC_REQ PID should indicate that it is off when disconnecting the connector. If the AC_REQ PID remains on, a short to GND circuit may be present. Does the AC_REQ PID remain on?	Yes	Inspect for short to GND circuit between refrigerant pressure switch and PCM terminal 4W.
3		No	Go to the next step.
4	Reconnect the refrigerant pressure switch connector. Read the AC_REQ PID while turning off the A/C switch. Note • The AC_REQ PID should indicate that it is off when turning the A/C switch off. If the AC_REQ PID remains on, a short to GND circuit may be present. Does the AC_REQ 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
4		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.