Mazda CX-9 Grand Touring. Manual - part 236

2



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



Is any related Service Bulletins 
available?  

Yes



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

No

Go to the next step.

3

INSPECT TP SENSOR CONNECTOR 
FOR POOR CONNECTION  



Turn the ignition switch off.  



Disconnect the throttle body 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 9.

No

Go to the next step.

4

INSPECT TP SENSOR CIRCUIT FOR 
SHORT TO GROUND  



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



Inspect for continuity between TP sensor 
terminal F (wiring harness-side) and 
body ground  



Is there continuity?  

Yes

Repair or replace suspected part, then go to 
Step 9.

No

Go to the next step.

5

INSPECT PCM CONNECTOR FOR POOR 
CONNECTION  



Turn the ignition switch off.  



Disconnect the PCM 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 9.

No

Go to the next step.

6

INSPECT TP SIGNAL CIRCUIT FOR 
OPEN CIRCUIT  



Inspect for continuity between throttle 
body connector terminal F (wiring 
harness-side) and PCM terminal 2Z 
(wiring harness-side).  



Is there continuity?  

Yes Go to the next step.

No

Repair or replace suspected part, then go to 

Step 9.

7

INSPECT TP GROUND CIRCUIT FOR 
OPEN CIRCUIT  



Turn the ignition switch off.  



Verify the continuity between TP sensor 
terminal E (wiring harness-side) and 

Yes Go to the next step.

Repair or replace suspected part, then go to 

 

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 77 

© 2005 Mitchell Repair Information Company, LLC. 

DTC P0123 [MZI-3.7] 

DTC P0123 (MZI-3.7) DETECTION CONDITIONS AND POSSIBLE CAUSES 

PCM terminal 2AH (wiring harness-
side).  



Is the continuity?  

No

Step 9.

8

INSPECT TP SENSOR NO.1  



Inspect the TP sensor No.1. (See 
THROTTLE POSITION (TP) 
SENSOR INSPECTION [MZI-3.7] .)  



Is there any malfunction?  

Yes

Replace the throttle body, then go to the next 
step.

No

Go to the next step.

9

VERIFY TROUBLESHOOTING OF DTC 
P0122 HAS BEEN COMPLETED  



Make sure to reconnect all disconnected 
connectors.  



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



Start the engine.  



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



Is 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.

10

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.

DTC P0123

TP sensor No.1 circuit high input

DETECTION 

CONDITION 



The TP sensor No.1 circuit was flagged as a concern by the PCM indicating a 
high voltage.  

POSSIBLE CAUSE 



TP sensor No.1 malfunction  



Connector or terminal malfunction  



Short to constant voltage supply circuit between throttle body terminal F and 
PCM terminal 2Z  



TP sensor signal circuits are shorted 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 10:08:35 AM

Page 78 

© 2005 Mitchell Repair Information Company, LLC. 

DIAGNOSTIC PROCEDURE 

DTC P0123 (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 
INFORMATION AVAILABILITY  

Yes Perform repair or diagnosis according to the 

available Service Bulletins. 

 

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 79 

© 2005 Mitchell Repair Information Company, LLC. 

2



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



Is any related Service Bulletins 
available?  



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

No

Go to the next step.

3

INSPECT TP SENSOR CONNECTOR 
FOR POOR CONNECTION  



Turn the ignition switch off.  



Disconnect the throttle body 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.

4

INSPECT PCM CONNECTOR FOR 
POOR CONNECTION  



Turn the ignition switch off.  



Disconnect the PCM 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.

5

INSPECT TP SIGNAL CIRCUIT FOR 
SHORT TO POWER SUPPLY  



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



Measure the voltage between Throttle 
body connector terminal F (wiring 
harness-side) and body ground.  



Is the voltage B+?  

Yes

Repair or replace suspected part, then go to Step 
8.

No

Go to the next step.

6

INSPECT TP SENSOR SIGNAL 
CIRCUITS FOR SHORT EACH OTHER 



Disconnect the TP sensor and PCM 
connector.  



Measure resistance between Throttle 
body connector terminal D and F  



Is the resistance more than 10 
kilohms?  

Yes Go to the next step.

No

Repair or replace suspected part, then go to Step 

8.

7

INSPECT TP SENSOR NO.1  



Inspect the TP sensor No.1. (See 
THROTTLE POSITION (TP) 
SENSOR INSPECTION [MZI-3.7] .) 

Yes

Replace the throttle body, 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 80 

© 2005 Mitchell Repair Information Company, LLC.