Mazda CX-9 Grand Touring. Manual - part 315

DIAGNOSTIC PROCEDURE 

DTC P2127 (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.

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 10:08:43 AM

Page 393 

© 2005 Mitchell Repair Information Company, LLC. 

2

INFORMATION AVAILABILITY  



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



Is any related Service Bulletins 
available?  

Yes

Perform repair or diagnosis according to the 
available Service Bulletins. 



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

No

Go to the next step.

3

INSPECT APP SENSOR CONNECTOR 
FOR POOR CONNECTION  



Turn the ignition switch off.  



Disconnect the APP 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

INSPECT APP SENSOR NO.2 
CIRCUIT FOR SHORT TO GROUND 



Turn the ignition switch off.  



Inspect for continuity between the 
following terminals: 



APP sensor terminal F and 
body ground.  



APP sensor terminal D and 
body ground.  



APP sensor terminal G and 
body ground.  



APP sensor terminal C and 
body ground.  



APP sensor terminal H and 
body ground.  



Are there continuity?  

Yes

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

No

Go to the next step.

5

INSPECT APP SENSOR NO.2  



Inspect APP sensor No.2. (See 
ACCELERATOR PEDAL 
POSITION (APP) SENSOR 
INSPECTION [MZI-3.7] .)  



Is there any malfunction?  

Yes

Replace the accelerator pedal, then go to Step 7. 
(See ACCELERATOR PEDAL 
REMOVAL/INSTALLATION [MZI-3.7] .)

No

Go to the next step.

INSPECT PCM CONNECTOR FOR 
POOR CONNECTION  

Yes

Repair or replace suspected part, then go to Step 

 

2008 Mazda CX-9 Grand Touring 

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

  

Microsoft 

 

Sunday, November 15, 2009 10:08:43 AM

Page 394 

© 2005 Mitchell Repair Information Company, LLC. 

DTC P2128 [MZI-3.7] 

DTC P2128 (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES 

6



Turn the ignition switch off.  



Disconnect the PCM connector.  



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



Are there any malfunction?  

7.

No

Go to the next step.

7

VERIFY TROUBLESHOOTING OF 
DTC P2127 HAS BEEN COMPLETED 



Verify that all disconnected 
connectors reconnected.  



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



Start the engine.  



Is the same 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.

8

VERIFY AFTER REPAIR 
PROCEDURE  



Perform the "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

DTC troubleshooting completed.

DTC P2128

APP sensor No.2 circuit high input

DETECTION 

CONDITION 



APP sensor No.2 is out of self-test range high.  

POSSIBLE CAUSE 



Open circuit wiring harness between APP sensor terminal F and PCM 
terminal 1BA  



Open circuit wiring harness between APP sensor terminal D and PCM 
terminal 1Y  



Open circuit wiring harness between APP sensor terminal G and PCM 
terminal 1 AD  



Open circuit wiring harness between APP sensor terminal C and PCM 
terminal 1 AH  



Open circuit wiring harness between APP sensor terminal H and PCM 
terminal 1 AG  



Snort to power supply in wiring harness between APP sensor terminal F and 
PCM terminal 1BA  



Short to power supply in wiring harness between APP sensor terminal D and 

 

2008 Mazda CX-9 Grand Touring 

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

  

Microsoft 

 

Sunday, November 15, 2009 10:08:43 AM

Page 395 

© 2005 Mitchell Repair Information Company, LLC. 

PCM terminal 1Y  



Short to power supply in wiring harness between APP sensor terminal G and 
PCM terminal 1 AD  



Short to power supply in wiring harness between APP sensor terminal C and 
PCM terminal 1AH  



Short to power supply in wiring harness between APP sensor terminal H and 
PCM terminal 1 AG  



Connector or terminal malfunction  



APP sensor malfunction  

 

2008 Mazda CX-9 Grand Touring 

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

  

Microsoft 

 

Sunday, November 15, 2009 10:08:43 AM

Page 396 

© 2005 Mitchell Repair Information Company, LLC.