Mazda CX-9 Grand Touring. Manual - part 212

Fig. 24: Identifying CMP And PCM Sensor Harness Side Connector 
Courtesy of MAZDA MOTORS CORP. 

1. Disconnect the PCM connector. (See PCM REMOVAL/INSTALLATION [MZI-3.7].)  

2. Inspect the following harness for open or short circuit. (Continuity check)  

Open circuit 



CMP sensor (RH) terminal A and PCM terminal 2X  



CMP sensor (RH) terminal B and PCM terminal 2C  



CMP sensor (LH) terminal A and PCM terminal 2AB  



CMP sensor (LH) terminal B and PCM terminal 2C  

Short circuit 



CMP sensor (RH) terminal A and power supply  



CMP sensor (RH) terminal A and body ground  



CMP sensor (RH) terminal B and power supply  



CMP sensor (LH) terminal A and power supply  



CMP sensor (LH) terminal A and body ground 

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Control System (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:07:19 AM

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

CMP sensor (LH) terminal B and power supply  

FRONT HEATED OXYGEN SENSOR (HO2S) REMOVAL/INSTALLATION 
[MZI-3.7] 

HO2S (LH) REMOVAL/INSTALLATION 

1. Disconnect the negative battery cable.  

2. Remove the engine cover. (See ENGINE COVER REMOVAL/INSTALLATION [MZI-3.7] .)  

3. Disconnect the HO2S (LH) connector. 

4. Remove the HO2S (LH) using the SST. 

5. Install in the reverse order of removal. 

Fig. 25: View Of HO2S (LH), SST & Torque Specifications 
Courtesy of MAZDA MOTORS CORP. 

HO2S (RH) REMOVAL/INSTALLATION 

1. Disconnect the negative battery cable.  

2. Remove the following part for easier access. 

1. Remove the cowl panel. (See COWL PANEL REMOVAL/INSTALLATION .)  

3. Disconnect the HO2S (RH) connector. 

NOTE:



If necessary, lubricate the HO2S with Penetrating and Lock Lubricant 
loosen to aid in removal.  

NOTE:



Apply a light coat of anti-seize lubricant to the threads of the HO2S. 

NOTE:



If necessary, lubricate the HO2S with Penetrating and Lock Lubricant 
loosen to aid in removal.  

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Control System (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:07:19 AM

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© 2005 Mitchell Repair Information Company, LLC. 

4. Remove the HO2S (RH) using the SST. 

5. Install in the reverse order of removal. 

Fig. 26: View Of HO2S, SST & Torque Specifications 
Courtesy of MAZDA MOTORS CORP. 

FRONT HEATED OXYGEN SENSOR (HO2S) INSPECTION [MZI-3.7] 

FRONT HEATED OXYGEN SENSOR (HO2S) VOLTAGE INSPECTION 

1. Warm up the engine to normal operating temperature.  

2. Using the M-MDS, monitor the following: 



Vehicle speed (PID: VSS)  



Engine speed (PID: RPM)  



Front HO2S voltage (PID: O2S11, O2S21)  

3. Drive the vehicle and decelerate the engine speed by releasing the accelerator pedal fully when the engine 

speed is 3,000 rpm or more.  

4. Verify that the front H02S outputs a voltage of 0.6 V or more , one time or more, then verify that the 

front HO2S voltage (PID: O2S11, O2S21) is 0.3 V is or less while decelerating as shown in the figure. 

NOTE:



Apply a light coat of anti-seize lubricant to the threads of the HO2S. 

NOTE:



Before performing the following inspection, make sure to follow the 
procedure as indicated in the troubleshooting flowchart. (See HOW TO 
USE THIS MANUAL .)  

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Control System (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:07:19 AM

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© 2005 Mitchell Repair Information Company, LLC. 

Fig. 27: Output Voltage Graph 
Courtesy of MAZDA MOTORS CORP. 



If not within the specification, inspect the front HO2S for an open or short circuit. (See FRONT 
HEATED OXYGEN SENSOR (HO2S) Voltage Inspection.) Then if there is no malfunction in 
the wiring harness, replace the front HO2S. (See FRONT HEATED OXYGEN SENSOR 
(HO2S) REMOVAL/INSTALLATION [MZI-3.7].)  

HO2S HEATER RESISTANCE INSPECTION 

1. Disconnect the HO2S connector.  

2. Measure the resistance between HO2S terminals C and A. 



If it is not within the specification, replace the HO2S. (See FRONT HEATED OXYGEN 
SENSOR (HO2S) REMOVAL/INSTALLATION [MZI-3.7].)  



If the monitor item status/specification (reference) is not within the specification, even though the 
resistance is within the specification, perform the "Circuit Open/Short Inspection".  

HO2S heater resistance  

3-30 ohms  

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Control System (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:07:19 AM

Page 30 

© 2005 Mitchell Repair Information Company, LLC.