Mazda CX-9 Grand Touring. Manual — part 269

DIAGNOSTIC PROCEDURE

DTC P0446 (MZI-3.7) DIAGNOSTIC PROCEDURE

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA
HAS BEEN RECORDED



Has FREEZE FRAME DATA been
recorded?

Yes Go to the next step.

No

Record FREEZE FRAME DATA on the repair

order, then go to the next step.

2

VERIFY RELATED REPAIR
INFORMATION AVAILABILITY



Verify related Service Bulletins
and/or on-line repair information
availability.



Is any related Service Bulletins

Yes

Perform repair or diagnosis according to the
available Service Bulletins.



If the vehicle is not repaired, go to the next
step.

2008 Mazda CX-9 Grand Touring

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

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available?

No

Go to the next step.

3

INSPECT CV SOLENOID VALVE
CONNECTOR FOR POOR
CONNECTION



Turn the ignition switch off.



Disconnect CV solenoid valve
connector.



Inspect for poor connection (such as
damaged/pulled-out pins,
corrosion).



Are there any malfunction?

Yes

Repair or replace suspected part, then go to Step
10.

No

Go to the next step.

4

INSPECT POWER SUPPLY
CIRCUIT FOR OPEN CIRCUIT



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



Measure voltage between CV
solenoid valve terminal A and body
ground.



Is voltage B+ ?

Yes Go to the next step.

No

Repair or replace suspected part, then go to Step

10.

5

INSPECT CV SOLENOID VALVE
CONTROL CIRCUIT FOR SHORT
TO POWER SUPPLY



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



Measure the voltage between CV
solenoid valve control terminal B
and body ground.



Is voltage B+?

Yes

Repair or replace suspected part, then go to Step
10.

No

Go to the next step.

6

INSPECT CV SOLENOID VALVE
CONTROL CIRCUIT FOR SHORT
TO GROUND



Turn the ignition switch off.



Inspect for continuity between CV
solenoid valve control terminal B
and body ground.



Is the continuity?

Yes

Repair or replace suspected part, then go to the
Step 10.

No

Go to the next step.

INSPECT PCM CONNECTOR FOR
POOR CONNECTION



Turn the ignition switch off.

Yes

Repair or replace suspected part, then go to Step
10.

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:08:38 AM

Page 210

© 2005 Mitchell Repair Information Company, LLC.

7



Disconnect PCM connector.



Inspect for poor connection (such as
damaged/pulled-out pins,
corrosion).



Is there any malfunction?

No

Go to the next step.

8

INSPECT CV SOLENOID VALVE
CONTROL CIRCUIT FOR OPEN
CIRCUIT



Turn the ignition switch off.



Inspect continuity between CV
solenoid valve terminal B and PCM
terminal 1Z.



Is there continuity?

Yes Go to the next step.

No

Repair or replace suspected part, then go to the

Step 10.

9

INSPECT CV SOLENOID VALVE



Inspect the CV solenoid valve. (See
CHARCOAL CANISTER,
CANISTER VENT (CV)
SOLENOID VALVE, AIR
FILTER COMPONENT
INSPECTION [MZI-3.7] .)



Is there any malfunction?

Yes

Replace CV solenoid valve (See CHARCOAL
CANISTER, CANISTER VENT (CV)
SOLENOID VALVE, AIR FILTER
COMPONENT REMOVAL/INSTALLATION
[MZI-3.7] .), then go to Step 10.

No

Go to the next step.

10

VERIFY TROUBLESHOOTING OF
DTC P0446 COMPLETED



Make sure to reconnect all
disconnected connectors.



Clear DTC from PCM memory
using M-MDS.



Perform the "KOEO or KOER self-
test" using the M-MDS. (See
KOEO/KOER SELF TEST
[MZI-3.7].)



Is the PENDING CODE same DTC
present?

Yes

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

No

Go to the next step.

11

VERIFY AFTER REPAIR
PROCEDURE



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



Are any DTCs present?

Yes

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

No

Troubleshooting completed.

2008 Mazda CX-9 Grand Touring

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

Microsoft

Sunday, November 15, 2009 10:08:38 AM

Page 211

© 2005 Mitchell Repair Information Company, LLC.

DTC P0451 [MZI-3.7]

DTC P0451 (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES

DIAGNOSTIC PROCEDURE

DTC P0451 (MZI-3.7) DIAGNOSTIC PROCEDURE

DTC P0451

Fuel tank pressure sensor range/performance

DETECTION

CONDITION



The fuel tank pressure changes more than 14 inches of water in 0.10 s. Fuel tank
pressure sensor output is offset by + /-1.7 inches of water.

NOTE:



For some vehicle applications, DTC P0451 is set for a fuel tank pressure
sensor range (offset) concern. The DTC P0454 replaces the original P0451
for intermittent (noisy) sensor concerns. Until the phase in process is
complete, noisy or offset fuel tank pressure sensor concerns may set DTC
P0451.

POSSIBLE

CAUSE



Intermittent open or short in the fuel tank pressure sensor or the fuel tank
pressure sensor signal



Fuel tank pressure sensor malfunction



Connector or terminal malfunction



PCM malfunction

STEP

INSPECTION

ACTION

1

VERIFY FREEZE FRAME DATA
HAS BEEN RECORDED



Has the FREEZE FRAME DATA
been recorded?

Yes Go to the next step.

No

Record FREEZE FRAME DATA on the repair

order, then go to the next step.

2

VERIFY RELATED REPAIR
INFORMATION AVAILABILITY



Verify related Service Bulletins
and/or on-line repair information
availability.



Is any related repair information
available?

Yes

Perform the repair or diagnosis according to the
available repair information.



If the vehicle is not repaired, go to the next
step.

No

Go to the next step.

3

VERIFY RELATED PENDING CODE
OR STORED DTCs



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



Verify related pending code or
stored DTCs.

Yes

Go to the appropriate DTC troubleshooting. (See
DTC TABLE [MZI-3.7].)

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 10:08:38 AM

Page 212

© 2005 Mitchell Repair Information Company, LLC.