NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZ-CD 1.6 (Y6)]

id0103b3804900

24

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

DESCRIPTION

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

POSSIBLE CAUSE

•  A/C compressor magnetic clutch stuck engagement

•  A/C relay is stuck closed

•  Improper A/C compressor magnetic clutch clearance

•  Short to GND circuit between A/C switch and PCM

•  Short to GND circuit between A/C relay and PCM

•  A/C relay to magnetic clutch circuit shorts to battery power

24	A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION	• The A/C compressor magnetic clutch does not disengage.
POSSIBLE CAUSE	• A/C compressor magnetic clutch stuck engagement • A/C relay is stuck closed • Improper A/C compressor magnetic clutch clearance • Short to GND circuit between A/C switch and PCM • Short to GND circuit between A/C relay and PCM • A/C relay to magnetic clutch circuit shorts to battery power

Diagnostic Procedure

STEP	INSPECTION	RESULTS	ACTION
1	Perform the self-test function using the M-MDS. Turn the engine switch to the ON position. Retrieve any DTC. Are DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC test. Communication error message is displayed: Inspect for the following: • Open circuit between PCM control relay and PCM terminal 236 or 231 • Open circuit between PCM control relay and PCM terminal 241 • PCM control relay stuck open • Open or poor ground circuit (PCM terminal 307, 308 or 332) • Poorly connected vehicle body ground
1		No	No DTC is displayed: Go to the appropriate DTC test.
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: • A/C relay is stuck closed • Short to ground between A/C relay and PCM terminal 112 If both items are normal, go to the next step.
2		No	Inspect if circuit between A/C relay and magnetic clutch shorts to battery power circuit. If circuit is normal, inspect magnetic clutch stuck engagement or clearance.
3	Start the engine and turn the A/C switch on. Measure the PCM terminal 303 voltage while disconnecting the refrigerant pressure switch connector. Примечание • The PCM terminal 303 voltage should read B+ when disconnecting the connector. If the PCM terminal 303 voltage reading remains below 1.0 V, short to ground circuit may be present. Is the voltage B+?	Yes	Inspect for short to ground circuit between refrigerant pressure switch and PCM terminal 303.
3		No	Go to the next step.
4	Reconnect the refrigerant pressure switch connector. Measure the PCM terminal 303 voltage while turning off the A/C switch. Примечание • The PCM terminal 303 voltage should read B+ when turning the A/C switch off. If the PCM terminal 84 voltage reading remains below 1.0 V, short to ground circuit maybe present. Does the voltage remain B+?	Yes	Inspect for the following: • Short to ground between A/C switch and A/C amplifier. • Short to ground 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 diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZ-CD 1.6 (Y6)].) • If the malfunction remains, inspect related Service Information and perform repair or diagnosis. ― If the vehicle is repaired, troubleshooting is completed. ― If the vehicle is not repaired or additional diagnostic information is not available, replace the PCM. (See PCM REMOVAL/INSTALLATION [MZ-CD 1.6 (Y6)].)