Mazda CX-9 Grand Touring. Manual - part 335

Connect the M-MDS to the DLC-2.
Start the engine and idle it.
Access LONG FT1 PID, LONG FT2 PID.
Measure LONG FT1 PID, LONG FT2 PID
at idle.
Is PID value normal?

LONG FT1 PID, LONG FT2 PID is out of

specification.

Less than specification (too rich):



Inspect EVAP control system.

Greater than specification (too lean):



Inspect for air leakage at intake-air

system components.



If system is normal, go to the

next step.

Disconnect the vacuum hose between the
purge solenoid valve and the intake
manifold from purge solenoid valve side.
Plug opening end of vacuum hose.
Start the engine.
Does the engine condition improve?

Yes

Check if purge solenoid valve is stuck
open mechanically.
Inspect EVAP control system.

Go to the next step.

Remove and shake the PCV valve.
Does the PCV valve rattle?

Yes

Go to the next step.

Replace the PCV valve.

Visually inspect the exhaust system part.
Is there any deformed exhaust system part?

Yes

Replace the suspected part.

Go to the next step.

Visually inspect the CMP sensor and teeth
of camshaft.
Are the CMP sensor and teeth of camshaft
normal?

Yes

Go to the next step.

Replace the malfunctioning part.

Inspect variable valve timing control
system operation.
(See ENGINE CONTROL SYSTEM
OPERATION INSPECTION [MZI-
3.7].)
Does variable valve timing control system
function properly?

Yes

Go to the next step.

Repair or replace the malfunctioning part.

Is engine compression correct?

Yes

Inspect the valve timing.

Inspect for causes.



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.

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:10:05 AM

Page 46

NO.9 FAST IDLE/RUNS ON [MZI-3.7]

NO.9 FAST IDLE/RUNS ON (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES

DIAGNOSTIC PROCEDURE

NO.9 FAST IDLE/RUNS ON (MZI-3.7) DIAGNOSTIC PROCEDURE



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

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

FAST IDLE/RUNS ON

DESCRIPTION



The engine speed continues at fast idle after warm-up.



The engine runs after the ignition switch is turned off.

POSSIBLE CAUSE



CHT sensor malfunction



Air leakage from intake-air system



Throttle body malfunction



Accelerator pedal position sensor misadjustment



Cruise control system operation improperly



Improper load signal input



Improper operation of electronic throttle control system

STEP

INSPECTION

RESULTS

ACTION

Connect the M-MDS to the DLC-2.
Access ECT PID.
Start and warm up engine to normal
operating temperature.
Is ECT PID between 82-112°C
{180-234°F}?

Yes

Go to the next step.

ECT PID is higher than 112°C {234°F}:

Go to symptom troubleshooting "No.17 Cooling

system concerns - Overheating".

ECT PID is less than 82°C {180°F}:

Go to symptom troubleshooting "No.18 Cooling

system concerns - Runs cold".

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 DTC is displayed:

Go to the next step.

Yes

Go to the next step.

If the AC_REQ PID is not normal:



Inspect A/C switch, refrigerant pressure

switch, and fan switch, and related wiring

harness for vibration or intermittent

open/short circuit.

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:10:05 AM

Page 47

NO.10 LOW IDLE/STALLS DURING DECELERATION [MZI-3.7]

NO.10 LOW IDLE/STALLS DURING DECELERATION (MZI-3.7) DETECTION CONDITIONS AND
POSSIBLE CAUSES

Access and monitor PSP and TR
PIDs.
Are PIDs values normal?
(See PCM INSPECTION [MZI-
3.7] .)

If the TR PID is not normal:



Inspect TR switch and related wiring

harness for vibration or intermittent

open/short circuit.

If the PSP PID is not normal:



Inspect power steering switch and related

wiring harness for vibration or intermittent

open/short circuit.

Is there air leakage felt or heard at
intake-air system components while
racing engine to higher speed?

Yes

Repair or replace parts if necessary.

Inspect the following:



Electronic throttle control system

operation



Accelerator pedal position sensor



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] .)

LOW IDLE/STALLS DURING DECELERATION

DESCRIPTION



Engine stops unexpectedly at the beginning of deceleration or recovery from
deceleration.



Vacuum leakage



Improper operation of electronic throttle control system



Air leakage from intake-air system

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:10:05 AM

Page 48

DIAGNOSTIC PROCEDURE

NO.10 LOW IDLE/STALLS DURING DECELERATION (MZI-3.7) DIAGNOSTIC PROCEDURE

POSSIBLE

CAUSE



Improper air/fuel mixture ratio control



Evaporative emission control system malfunction



Accelerator pedal position sensor or related circuit malfunction



Accelerator pedal position sensor misadjustment



TP sensor or related circuit malfunction



MAF sensor or related circuit malfunction



Brake switch or related circuit malfunction



TR switch or related circuit malfunction



Improper A/C magnetic clutch operation

STEP

INSPECTION

RESULTS

ACTION

Does the engine idle roughly?

Yes

Go to symptom troubleshooting "No.8
Engine runs rough/rolling idle".
(See NO.8 ENGINE RUNS
ROUGH/ROLLING IDLE [MZI-3.7].)

Go to the next step.

Turn off the A/C switch and fan switch.
Does the A/C magnetic clutch engage?

Yes

Go to symptom troubleshooting "No.24 A/C
is always on or A/C compressor runs
continuously."
(See NO.24 A/C IS ALWAYS ON OR A/C
COMPRESSOR RUNS
CONTINUOUSLY [MZI-3.7].)

Go to the next step.

Verify the following:



Proper routing of and no damage
to vacuum lines



No air leakage from intake-air
system

Are all items normal?

Yes

Go to the next step.

Service if necessary.

Repeat Step 3.

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 DTC is displayed:

Go to the next step.

Perform the electronic throttle control
system operation inspection.
(See ENGINE CONTROL SYSTEM

Yes

Go to the next step.

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:10:05 AM

Page 49

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