NO.26 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY [MZR-CD (RF Turbo)]

id0103f1822400

26

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

DESCRIPTION

•  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 ground circuit between A/C switch and PCM

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

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

26	A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
DESCRIPTION	• 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 ground circuit between A/C switch and PCM • Short to ground 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 DTCs. Are any DTCs displayed?	Yes	DTC is displayed: Go to the appropriate DTC test. (See DTC TABLE [MZR-CD (RF Turbo)].) Communication error message is displayed: Inspect the following: • Open circuit between PCM control relay and PCM terminal 119 or 120 • Open circuit PCM control relay and PCM terminal 105 • PCM control relay stuck open • Open or poor ground circuit (PCM terminal 1, 2, 3, 114 or 117) • Poor connection to vehicle body ground
1		No	No DTC is displayed: Go to the appropriate DTC test. (See DTC TABLE [MZR-CD (RF Turbo)]..)
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 the following: • A/C relay is stuck closed • Short to ground circuit between A/C relay and PCM terminal 26 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 PCM terminal 32 voltage while disconnecting the refrigerant pressure switch connector. Note • PCM terminal 32 voltage should read B+ when disconnecting the connector. If the PCM terminal 32 voltage reading remains below 1.0 V, a short to ground circuit may be present. Is the voltage B+?	Yes	Inspect for a short to ground circuit between the refrigerant pressure switch and PCM terminal 32.
3		No	Go to the next step.
4	Reconnect the refrigerant pressure switch connector. Measure PCM terminal 32 voltage while turning off the A/C switch. Note • PCM terminal 32 voltage should read B+ when turning the A/C switch off. If the PCM terminal 32 voltage reading remains below 1.0 V, a short to ground circuit maybe present. Does the voltage remain B+?	Yes	Inspect the following: • Short to ground circuit between A/C switch and A/C amplifier. • Short to ground circuit between A/C amplifier and refrigerant pressure switch.
4		No	Inspect for a stuck closed A/C switch.
5	Verify test results. • If normal, return to the diagnostic index to service any additional symptoms. (See SYMPTOM DIAGNOSTIC INDEX [MZR-CD (RF Turbo)].) • If the malfunction remains, inspect the related Service Information and perform repair or diagnosis. ― If the vehicle is repaired, troubleshooting completed. ― If the vehicle is not repaired or additional diagnostic information is not available, reprogram the PCM if later calibration is available. Retest.