Mazda 3 Workshop Manual page 611

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY.
A/C compressor magnetic clutch does not disengage.
DESCRIPTION
• Stuck engagement A/C compressor magnetic clutch
• A/C relay is stuck closed.
• Short to GND in wiring harness between A/C switch and PCM
POSSIBLE CAUSE
• Short to GND in wiring harness between A/C relay and PCM
• Short circuit to battery power in A/C relay to magnetic clutch
Diagnostic procedure
STEP
Connect the WDS or equivalent to the DLC-2.
Retrieve any continuous memory, KOEO and
1
KOER DTCs using WDS or equivalent.
Are there any DTCs displayed?
Start the engine and idle it.
Turn the A/C switch on.
2
Remove the A/C relay.
Does the A/C magnetic clutch disengage?
Connect WDS or equivalent to DLC-2.
Access AC_REQ PID.
Start engine and turn A/C switch on.
3
Read AC_REQ PID while disconnecting
refrigerant pressure switch connector.
Note
• AC_REQ PID should read Off when
disconnecting connector. If AC_REQ PID
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INSPECTION
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RESULTS ACTION
DTC is displayed:
Yes
Go to appropriate DTC inspection.
(See DTC TABLE
No DTC is displayed:
No
Go to the next step.
Inspect for following:
• The A/C relay is stuck closed.
• Short to GND in wiring harness
Yes
between A/C relay and PCM
terminal 1AN.
If both items normal, go to the next
step.
Inspect if circuit between the A/C
relay and magnetic clutch shorts to
battery power circuit.
No
• If the circuit is normal, inspect for
magnetic clutch stuck engagement
or clearance.
Inspect for short to GND in wiring
harness between refrigerant
Yes
pressure switch and PCM terminal
1AP.
No Go to the next step.
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