NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [ZJ, ZY]

id0103b0803000

24

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

DESCRIPTION

•  The A/C compressor magnetic clutch does not disengage.

POSSIBLE CAUSE

•  Continuous memory DTC is stored

•  A/C relay malfunction (stuck closed)

•  Short to ground in wiring harness between A/C relay and PCM

•  Short to power supply in wiring harness between A/C relay and magnetic clutch

•  Stuck engagement A/C compressor magnetic clutch

•  Short to ground in wiring harness between refrigerant pressure switch and PCM

•  Short to ground in wiring harness between A/C switch and A/C amplifier

•  Short to ground in wiring harness between A/C switch and A/C amplifier

•  Short to ground in wiring harness between A/C amplifier and refrigerant pressure switch

•  A/C switch malfunction (stuck closed)

•  PCM malfunction

24	A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION	• The A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE	• Continuous memory DTC is stored • A/C relay malfunction (stuck closed) • Short to ground in wiring harness between A/C relay and PCM • Short to power supply in wiring harness between A/C relay and magnetic clutch • Stuck engagement A/C compressor magnetic clutch • Short to ground in wiring harness between refrigerant pressure switch and PCM • Short to ground in wiring harness between A/C switch and A/C amplifier • Short to ground in wiring harness between A/C switch and A/C amplifier • Short to ground in wiring harness between A/C amplifier and refrigerant pressure switch • A/C switch malfunction (stuck closed) • PCM malfunction

Diagnostic procedure

STEP	INSPECTION	ACTION
1	Connect the M-MDS to the DLC-2. Perform the KOEO/KOER self test. (See KOEO/KOER SELF TEST [ZJ, ZY].) Are any continuous memory DTCs present?	Yes	Go to the appropriate DTC inspection. (See DTC TABLE [ZJ, ZY].)
1		No	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 the following: • A/C relay is stuck closed • Wiring harness between A/C relay and PCM terminal 1AN for short to ground ― If there is a malfunction: • Repair or replace the malfunctioning part according to the inspection results. ― If there is no malfunction: • Go to the next step.
2		No	Inspect the wiring harness between the A/C relay and the magnetic clutch for short to power supply. • If the wiring harness has a malfunction: ― Repair or replace the suspected wiring harness. • If the wiring harness is normal: ― Inspect the magnetic clutch stuck engagement or clearance. ― Repair or replace the malfunctioning part according to the inspection results.
3	Connect the M-MDS to the DLC-2. Perform the PID/DATA Monitor and Record Procedure and access the AC_REQ PID. (See ON-BOARD DIAGNOSTIC TEST [ZJ, ZY].) Start the engine and turn the A/C switch on. Read the AC_REQ PID while disconnecting the refrigerant pressure switch connector. Note • AC_REQ PID should read Off when disconnecting the connector. If the AC_REQ PID remains On, short to ground may be present. Does the AC_REQ PID remain On?	Yes	Inspect the wiring harness between the refrigerant pressure switch and the PCM terminal 1AO for short to ground. Repair or replace the wiring harness for a possible short to ground, if necessary.
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 • AC_REQ PID should read Off when turning the A/C switch off. If the AC_REQ PID remains On, short to ground may be present. Does the AC_REQ PID remain On?	Yes	Inspect the following: • Wiring harness between A/C switch and A/C amplifier for short to ground • Wiring harness between A/C amplifier and refrigerant pressure switch for short to ground Repair or replace the wiring harness for a possible short to ground, if necessary.
4		No	Inspect the A/C switch for stuck closed. Replace the A/C switch, if necessary.
5	Verify test results. • If normal, return to diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [ZJ, ZY].) • If malfunction remains, inspect related Service information perform repair or diagnosis. ― If vehicle repaired, troubleshooting completed. ― If vehicle not repaired or additional diagnostic information not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [ZJ, ZY].)