Mazda CX-9 Grand Touring. Manual — part 244

6



Locate the vacuum hose joint for the intake
air and PCV systems.



Access the PCM and monitor the SHRTFT1
and SHRTFT2 PIDs.



Restrict the vacuum lines one at a time for 30
s. If a vacuum leak in the intake is present,
the SHRTFT PID values decrease as the hose
is restricted.



Is the decrease in the SHRTFT PIDs more
than 15% when one of the vacuum hoses is
restricted?

NOTE:



Restricting the EVAP vapor hose while the
EVAP emission canister is purging may
shift the SHRTFT. Perform a visual
inspection if necessary.



When monitoring for a decrease in the
SHRTFT PIDs in the following steps, if
SHRTFT1 equals +15% and the hose is
restricted, SHRTFT1 decreases to-7%. The
total decrease in the SHRTFT PIDs equals
22%.

No

Inspect the intake air system for a vacuum

leak in the intake manifold or intake

gaskets. Repair if necessary. Then go to

the next step.

7

VACUUM LEAK REPAIR VERIFICATION



Access the PCM and monitor the SHRTFT1
and SHRTFT2 PIDs.



Allow the engine to stabilize at the
temperature necessary to recreate the
concern.



Record the SHRTFT1 and SHRTFT2 PID
values.



Turn the ignition switch off.

NOTE:



If the freeze frame ECT PID is available,
stabilize the engine at the temperature
recorded by the freeze frame ECT PID. If
the freeze frame ECT PID is not available,
maintain the engine coolant temperature
between 82-101°C {180-215°F} and the
intake air temperature less than 46°C {115°
F}.

Yes

Reset the keep alive memory. Then go to
Step 13.

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:35 AM

Page 109

© 2005 Mitchell Repair Information Company, LLC.



Repair the vacuum leak.



Turn the ignition switch to the ON position
(Engine running)



Allow the engine to stabilize at the
temperature necessary to recreate the
concern.



Access the PCM and monitor the SHRTFT1
and SHRTFT2 PIDs.



Compare the recorded SHRTFT PID values,
prior to the no vacuum leak repair, to the
current SHRTFT PID values.



Is the decrease in the SHRTFT PIDs more
than 15%?

No

A vacuum leak is still present. Go to Step

6.

8

INSPECT FUEL PRESSURE



Remove the jumper wire(s).



Connect the HO2S connector.



Relieve the fuel pressure.



Connect the mechanical fuel pressure gauge.



Pressurize the fuel system.



Turn the ignition switch to the ON position
(Engine running)



Allow the fuel pressure to stabilize.



Turn the ignition switch off.



Access the PCM and control the FP PID.



Run the fuel pump to obtain maximum fuel
pressure.



Is the fuel pressure within the range for the
vehicle being diagnosed?

WARNING:



Fuel line spills and leakage are dangerous.
Fuel can ignite and cause serious injuries
or death. Fuel can also irritate skin and
eyes. To prevent this, always complete the
"BEFORE REPAIR PROCEDURE".

NOTE:



For vehicle specific fuel pressure ranges,
refer to the "FUEL LINE PRESSURE
INSPECTION ".

Yes Go to Step 10.

No

Go to the next step.

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:35 AM

Page 110

© 2005 Mitchell Repair Information Company, LLC.

9

INSPECT FUEL LINE FROM FUEL PUMP
TO FUEL DELIVERY PIPE



Visually inspect fuel line for any leakage.



Is fuel leakage found?

Yes

Replace suspected fuel line. Then go to
Step 13.

No

Inspect the low-pressure side fuel filter

for the following:



Foreign materials or stain inside

fuel filter. Perform the following

actions as a result.



If foreign material or staining is

found inside the fuel filter (low-

pressure side), clean the fuel tank

and filter.



If normal, replace fuel pump unit.

Then go to Step 13.

10

INSPECT FUEL INJECTOR OPERATION



Remove fuel injector.



Inspect the injector operation.



Is the fuel injector normal?

Yes Go to the next step.

No

Replace the fuel injector, then go to Step

13.

11

INSPECT FRONT HO2S OUTPUT VOLTAGE



Visually inspect the HO2S circuit for
exposed wiring, contamination, corrosion and
correct assembly. Repair if necessary.



Measure the voltage between HO2S terminal
B and D on the component side.



Increase the engine speed to 2,000 rpm for 3
min.



Turn the ignition switch to the ON position
(Engine running)



Monitor the signal voltage.



Is the voltage more than 0.5 V at any time
during the engine running?

Yes Go to the next step.

No

Replace the HO2S. Then go to Step 13.

12

PERFORM THOROUGH WIGGLE TEST ON
HO2S WIRING HARNESS



Turn the ignition switch off.



Connect the HO2S connector.



Turn the ignition switch to the ON position
(Engine running)



Verify that the engine is at normal operating

Yes

Isolate the concern and repair if
necessary. Then go to the next step.

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:35 AM

Page 111

© 2005 Mitchell Repair Information Company, LLC.

DTC P0172, P0175 [MZI-3.7]

DTC P0172, P0175 (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES

temperature.



Access the PCM and monitor the HO2S
signal PID.



Wiggle, shake, and bend small sections of the
wiring harness while working from the
sensor to the PCM.



While monitoring the HO2S PID, does the
HO2S stop switching?

No

Go to the next step.

13

VERIFY TROUBLESHOOTING OF DTC
P0171, P0174 HAS BEEN COMPLETED



Verify that all disconnected connectors are
reconnected.



Turn the ignition switch to the ON position
(Engine off).



Clear the DTC from the PCM memory using
the M-MDS.



Start the engine and run it at idle.



Retrieve DTCs using the M-MDS.



Is the PENDING CODE for this DTC
present?

Yes

Replace PCM, then go to the next step.
(See PCM
REMOVAL/INSTALLATION [MZI-
3.7] .)

No

Go to the next step.

14

VERIFY AFTER REPAIR PROCEDURE



Perform "AFTER REPAIR PROCEDURE".
(See AFTER REPAIR PROCEDURE
[MZI-3.7].)



Are any DTC present?

Yes

Go to the applicable DTC inspection.
(See DTC TABLE [MZI-3.7].)

No

Troubleshooting completed.

DTC P0172

P0172: System too rich (RH)

DTC P0175

P0175: System too rich (LH)

DETECTION

CONDITION



P0172 indicates that the fuel/air ratio is too rich (RH).



P0175 indicates that the fuel/air ratio is too rich (LH).



The adaptive fuel strategy continuously monitors the fuel delivery hardware.
The test fails when the adaptive fuel tables reach a rich calibrated limit.

Fuel System:



Damaged or leaking fuel pulse damper



Leaking fuel injectors



Fuel return line restricted

2008 Mazda CX-9 Grand Touring

2008 ENGINE PERFORMANCE On-Board Diagnostic (MZI-3.7) - Mazda CX-9

Microsoft

Sunday, November 15, 2009 10:08:35 AM

Page 112

© 2005 Mitchell Repair Information Company, LLC.