Mazda Mazda6 - Page 375

TROUBLESHOOTING
F2–223
F2
NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
A6E408018881226
Diagnostic Procedure
End Of Sie
24 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 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
STEP INSPECTION RESULTS ACTION
1 Perform self-test function using WDS or
equivalent.
Turn engine switch to ON.
Retrieve any DTC.
Is DTC displayed?
Yes DTC is displayed:
Go to appropriate DTC test.
Communication error message is displayed:
Inspect for following:
• Open circuit between PCM control relay and PCM
terminal 53 or 79
• Open circuit PCM control relay and PCM terminal
69
• PCM control relay stuck open
• Open or poor GND circuit (PCM terminal 65, 85,
103 or 104)
• Poor connection vehicle body GND
No No DTC is displayed:
Go to appropriate DTC test.
2 Start engine and run it at idle.
Turn A/C switch on.
Remove A/C relay.
Does A/C magnetic clutch disengage?
Yes Inspect for following:
• A/C relay is stuck closed
• Short to GND circuit between A/C relay and PCM
terminal 73
If both items are okay, go to next step.
No Inspect if circuit between A/C relay and magnetic
clutch shorts to battery power circuit.
If circuit is okay, inspect magnetic clutch stuck
engagement or clearance.
3 Start engine and turn A/C switch on.
Measure PCM terminal 84 voltage while
disconnecting refrigerant pressure switch
connector.
Note
• PCM terminal 84 voltage should read B+
when disconnecting connector. If PCM
terminal 84 voltage reading remains
below 1.0 V, short to GND circuit may be
present.
Is voltage B+?
Yes Inspect for short to GND circuit between refrigerant
pressure switch and PCM terminal 84.
No Go to next step.
4 Reconnect refrigerant pressure switch
connector.Measure PCM terminal 84 voltage
while turning off A/C switch.
Note
• PCM terminal 84 voltage should read B+
when turning A/C switch off. If PCM
terminal 84 voltage reading remains
below 1.0 V, short to GND circuit maybe
present.
Does voltage remain B+?
Yes Inspect for 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.
No Inspect for stuck closed A/C switch.
5 Verify test results.
• If okay, return to diagnostic index to service any additional symptoms.
• If malfunction remains, replace PCM. (See F2–64 PCM REMOVAL/INSTALLATION)