Mazda CX-9 Grand Touring. Manual - part 270



Is other DTCs present?  

4

CLEAR AND ATTEMPT TO 
RETRIEVE THE DTC  



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



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



Run the engine for approx. 10 s .  



Check for continuous memory 
DTCs.  



Is the same DTC present?  

Yes Go to the next step.

No

DTC troubleshooting completed.

5

INSPECT FUEL TANK PRESSURE 
AND PCM SENSOR CONNECTOR 
FOR POOR CONNECTION  



Turn the ignition switch off.  



Disconnect the MAF/IAT sensor 
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 8.

No

Go to the next step.

6

INSPECT THE FUEL TANK 
PRESSURE  



Inspect the MAF sensor. (See FUEL 
TANK PRESSURE SENSOR 
INSPECTION [MZI-3.7] .)  



Is there malfunction?  

Yes

Replace evaporative hose component, then go to 
Step 8. (See FUEL TANK 
REMOVAL/INSTALLATION [MZI-3.7] .)

No

Go to the next step.

7

INSPECT FOR CORRECT PCM 
OPERATION  



Disconnect all the PCM connectors.  



Visually inspect for: 



Pushed out pins  



Corrosion  



Connect all the PCM connectors and 
verify that they seat correctly.  



Retrieve DTCs using the M-MDS.  



Is the PENDING CODE for this 
DTC present?  

Yes Go to the next step.

No

The system is correctly. Go to the next step.

VERIFY TROUBLESHOOTING OF 

 

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 213 

© 2005 Mitchell Repair Information Company, LLC. 

DTC P0452 [MZI-3.7] 

DTC P0452 (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES 

8

DTC P0451 COMPLETED  



Verify that all disconnected 
connectors are reconnected.  



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



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



Start the engine and wait for 
approx. 10s.  



Is the PENDING CODE for the 
DTC present?  

Yes

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

No

Go to the next step.

9

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

DTC troubleshooting completed.

DTC P0452

Fuel tank pressure sensor low input

DETECTION 

CONDITION 



The PCM monitors the evaporative emission (EVAP) control system fuel tank 
pressure sensor input signal to the PCM. The test fails when the signal average drops
below a minimum allowable calibrated parameter.  

POSSIBLE 

CAUSE 



Fuel tank pressure sensor malfunction  



Connector or terminal malfunction  



Short to ground between fuel tank pressure sensor terminal A and PCM terminal 1 
AB  



Fuel tank pressure sensor signal circuit and ground circuit for short each other  

 

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 214 

© 2005 Mitchell Repair Information Company, LLC. 

DIAGNOSTIC PROCEDURE 

DTC P0452 (MZI-3.7) DIAGNOSTIC PROCEDURE 

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.

VERIFY RELATED REPAIR 

 

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 215 

© 2005 Mitchell Repair Information Company, LLC. 

2

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

INSPECT FUEL TANKE PRESSURE 
SENSOR CONNECTOR FOR POOR 
CONNECTION  



Turn the ignition switch off.  



Disconnect the fuel tank pressure 
sensor 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 
7.

No

Go to the next step.

4

VERIFY FUEL TANK PRESSURE 
SIGNAL CIRCUIT FOR SHORT TO 
GROUND  



Turn the ignition switch off.  



Inspect for continuity between fuel 
tank pressure sensor terminal A 
(wiring harness-side) and body 
ground.  



Is there continuity?  

Yes

Repair or replace suspected part, then go to Step 
7.

No

Go to the next step.

5

INSPECT FUEL TANKE PRESSURE 
SENSOR SIGNAL CIRCUIT AND 
GROUND CIRCUIT FOR SHORT 
EACH OTHER  



Turn the ignition switch off.  



Disconnect the fuel tank pressure 
sensor and PCM connector.  



Measure resistance between PCM 
terminal 1AB (wiring harness-side) 
and PCM terminal 1AL (wiring 
harness-side)  



Is the resistance more than 10 
kilohms?  

Yes Go to the next step.

No

Repair or replace suspected part, then go to Step 

7.

INSPECT FUEL TANKE PRESSURE 
SENSOR  

Yes 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 216 

© 2005 Mitchell Repair Information Company, LLC.