Mazda CX-9 Grand Touring. Manual — part 344

DIAGNOSTIC PROCEDURE

NO.23 A/C DOES NOT WORK SUFFICIENTLY (MZI-3.7) DIAGNOSTIC PROCEDURE

POSSIBLE

CAUSE



Open the A/C magnetic clutch



Open circuit in wiring harness between A/C relay and A/C magnetic clutch



Poor GND of A/C magnetic clutch



Refrigerant pressure switch is stuck open.



A/C relay is stuck open.



Seized A/C compressor



Open circuit in wiring harness between A/C switch and PCM through both
refrigerant pressure switch and A/C amplifier

STEP

INSPECTION

RESULTS

ACTION

1

Connect the M-MDS to the DLC-
2.
Turn the ignition switch to the
ON position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?

Yes

DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [MZI-3.7] .)

No

No DTC is displayed:

Go to the next step.

2

Disconnect A/C compressor
connector.
Start engine and turn A/C switch
on.
Is there correct voltage at A/C
compressor magnetic clutch
terminal?
Specification
10.5 V or more

Yes

Inspect for GND condition of magnetic clutch on
A/C compressor.
If GND condition is normal, inspect for open circuit
magnetic clutch coil.

No

Go to the next step.

3

Disconnect refrigerant pressure
switch connector.
Connect jumper wiring between
A/C high pressure switch
terminal.
Connect jumper wiring between
refrigerant pressure switch
terminal.
Turn the ignition switch to the
ON position.
Turn A/C switch on and set
blower fan to any speed.
Does A/C work?

Yes

Inspect refrigerant pressure switch operation.
If switch is normal, go to the next step.

No

Inspect for the following:



A/C switch is stuck open.



Open circuit in wiring harness between

refrigerant pressure switch and PCM terminal

1R



Open circuit in wiring harness between

blower motor fan switch and resistor (if

blower motor does not operate)



Evaporator temperature sensor and A/C

amplifier

Remove jumper wiring from the
switch connector.

Yes

Inspect whether A/C relay is stuck open.
Replace if necessary.

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

Page 82

© 2005 Mitchell Repair Information Company, LLC.

NO.24 A/C IS ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY
[MZI-3.7]

NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY (MZI-3.7) DETECTION
CONDITIONS AND POSSIBLE CAUSES

DIAGNOSTIC PROCEDURE

NO.24 A/C ALWAYS ON OR A/C COMPRESSOR RUNS CONTINUOUSLY (MZI-3.7) DIAGNOSTIC
PROCEDURE

4

Reconnect connector to
refrigerant pressure switch.
Start the engine and turn the A/C
switch on.
Does the fan operate?

No

Inspect the following and repair or replace if

necessary:



Refrigerant charging amount



A/C compressor for seizure

5



Verify test results.



If normal, return to diagnostic index to service any additional symptoms.

(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)



If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.



If vehicle is repaired, troubleshooting completed.



If vehicle is not repaired or additional diagnostic information is not available,
replace the PCM.

(See PCM REMOVAL/INSTALLATION [MZI-3.7] .)

24

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

DESCRIPTION

A/C compressor magnetic clutch does not disengage.

POSSIBLE CAUSE



A/C compressor magnetic clutch engagement is stuck.



A/C relay is stuck closed.



Short to GND in wiring harness between A/C switch and PCM



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



Short circuit to battery power in A/C relay to magnetic clutch

STEP

INSPECTION

RESULTS

ACTION

1

Connect the M-MDS to the DLC-2.
Turn the ignition switch to the ON position
(Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?

Yes

DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [MZI-3.7] .)

No

No DTC is displayed:

Go to the next step.

Inspect for the following:

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

Page 83

© 2005 Mitchell Repair Information Company, LLC.

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



A/C relay is stuck closed.



Short to GND in wiring harness
between A/C relay and PCM
terminal 1N.

If both items normal, go to the next
step.

No

Inspect if circuit between the A/C

relay and magnetic clutch shorts to

battery power circuit.

If the circuit is normal, inspect the

magnetic clutch for stuck engagement

or clearance.

3

Disconnect refrigerant pressure switch
connector.
Start the engine and turn A/C switch on.

Does the A/C remain working?

NOTE:



A/C should not work when
disconnecting connector. If A/C
remains working, short to GND circuit
may be present.

Yes

Inspect for short to GND in wiring
harness between refrigerant pressure
switch and PCM terminal 1R.

No

Go to the next step.

4

Reconnect refrigerant pressure switch
connector.
Turn off A/C switch.

Does A/C remain working?

NOTE:



A/C should not work when turning A/C
switch off. If A/C remains working,
short to GND circuit may be present.

Yes

Inspect following:



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



Short to GND circuit between
A/C amplifier and refrigerant
pressure switch

No

Inspect whether A/C switch is stuck

closed.

5



Verify test results.



If normal, return to diagnostic index to service any additional symptoms.

(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)



If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

Page 84

© 2005 Mitchell Repair Information Company, LLC.

NO.25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE
CONDITIONS [MZI-3.7]

NO.25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS (MZI-3.7)
DETECTION CONDITIONS AND POSSIBLE CAUSES

DIAGNOSTIC PROCEDURE

NO.25 A/C DOES NOT CUT OFF UNDER WIDE OPEN THROTTLE CONDITIONS (MZI-3.7)
DETECTION CONDITIONS AND POSSIBLE CAUSES



If vehicle is repaired, troubleshooting completed.



If vehicle is not repaired or additional diagnostic information is not available,
replace the PCM.

(See PCM REMOVAL/INSTALLATION [MZI-3.7] .)

25

A/C DOES NOT CUT OFF UNDER WOT CONDITIONS.

DESCRIPTION

A/C compressor magnetic clutch does not disengage under WOT.

POSSIBLE CAUSE



Accelerator pedal position sensor malfunction



Accelerator pedal position sensor misadjustment



Loosely installed accelerator pedal position sensor

STEP

INSPECTION

RESULTS

ACTION

1

Does A/C compressor
disengage when the A/C switch
is turned off?

Yes

Go to the next step.

No

Go to symptom troubleshooting "NO.24 A/C IS

ALWAYS ON OR A/C COMPRESSOR RUNS

CONTINUOUSLY".

2

Connect the M-MDS to the
DLC-2.
Turn the ignition switch to the
ON position (Engine off).
Retrieve any DTCs.
Are there any DTCs displayed?

Yes

DTC is displayed:
Go to the appropriate DTC inspection.
(See DTC TABLE [MZI-3.7] .)

No

No DTC is displayed:

Inspect accelerator pedal position sensor.

3



Verify test results.



If normal, return to diagnostic index to service any additional symptoms.

(See SYMPTOM DIAGNOSTIC INDEX [MZI-3.7].)



If malfunction remains, inspect related Service Bulletins and/or On-line Repair
Information and perform repair or diagnosis.



If vehicle is repaired, troubleshooting completed.



If vehicle is not repaired or additional diagnostic information is not available,
replace the PCM.

2008 Mazda CX-9 Grand Touring

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:10:06 AM

Page 85

© 2005 Mitchell Repair Information Company, LLC.