Mazda CX-9 Grand Touring. Manual - part 349

GND system inspection for variable resistance type 2



Confirm that terminal sensor #4 is at 0 V. 



If it is at 0 V , inspect the sensor. 



If necessary, replace the sensor.  



If not at 0 V , inspect for the following: 



Open circuit in wiring harness  



Female terminal opening is loose.  



Coupler (pin holder) damage  



Pin discoloration (blackness)  



Harness/pin crimp is loose or disconnected.  

Input signal system inspection for variable resistance type 2 

1. When an irregular signal is detected, measure the #1 PCM terminal voltage. 



If the #1 terminal voltage and the M-MDS monitor voltage are the same, proceed to the next step.  



If there is a difference of 0.5 V or more , inspect for the following points concerning the PCM 
connector: 



Female terminal opening is loose.  



Coupler (pin holder) damage  



Pin discoloration (blackness)  



Harness/pin crimp is loose or disconnected.  

2. Measure the #2 sensor terminal voltage. 



If there is a 0.5 V or more difference between the sensor and the M-MDS voltages, inspect the 
wiring harness for open or short circuits.  



If the sensor and the M-MDS voltages are the same, inspect the following points concerning the 
sensor connector: 



Female terminal opening is loose.  



Coupler (pin holder) damage  



Pin discoloration (blackness)  



Harness/pin crimp is loose or disconnected.  



If there are no problems, proceed to next investigation below.  

Electrical supply system inspection for variable resistance type 2 



Confirm that the sensor #3 terminal is B+. 



If the measured voltage on the #3 terminal is B+ , inspect the following points on the sensor 
connector.  



If there is no problem, inspect for the following: 



Female terminal opening is loose.  



Coupler (pin holder) damage 

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:10:06 AM

Page 102 

© 2005 Mitchell Repair Information Company, LLC. 



Pin discoloration (blackness)  



If the #3 terminal measures other than B+ , inspect the following: 



Open or short circuit in wiring harness  



Harness/pin crimp is loose or disconnected.  

Thermistor type (IAT sensor & CHT sensor) 

Fig. 15: Thermistor Resistance Type (IAT Sensor & CHT Sensor) 
Courtesy of MAZDA MOTORS CORP. 

Input signal system inspection for thermistor type 

1. When an irregular signal is detected, measure the #1 PCM terminal voltage. 



If the #1 terminal voltage and the M-MDS monitor voltage are the same, proceed to the next step.  



If there is a difference of 0.5 V or more , inspect the following points concerning the PCM 
connector: 



Female terminal opening loose  



Coupler (pin holder) damage  



Pin discoloration (blackness)  



Harness/pin crimp is loose or disconnected.  

2. Measure the #2 sensor terminal voltage. 



If there is a 0.5 V or more difference between the sensor and the M-MDS voltages, inspect the 
wiring harness for open or short circuits.  



If the sensor and the M-MDS voltages are the same, inspect the following points concerning the 
sensor connector: 



Female terminal opening is loose.  



Coupler (pin holder) damage  



Pin discoloration (blackness)  



Harness/pin crimp is loose or disconnected.  



If there are no problems, proceed to next investigation below.  

GND system inspection for thermistor type 



Confirm that terminal sensor #3 is at 0 V.

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:10:06 AM

Page 103 

© 2005 Mitchell Repair Information Company, LLC. 



If it is at 0 V , inspect the sensor. If necessary, replace the sensor.  



If not, inspect for the following: 



Open circuit in wiring harness  



Female terminal opening is loose.  



Coupler (pin holder) damage  



Pin discoloration (blackness)  



Harness/pin crimp is loose or disconnected.  

MAIN RELAY OPERATION INSPECTION 

1. Verify that the main relay clicks when the ignition switch is turned to ON position and off. 



If there is no operation sound, inspect the following: 



Main relay (See RELAY INSPECTION .)  



Harness and connector between battery and main relay terminal A.  



Harness and connector between PCM terminal 1Q and main relay terminal E.  

ELECTRONIC THROTTLE CONTROL SYSTEM INSPECTION 

Engine coolant temperature compensation inspection 

1. Connect the M-MDS to the DLC-2.  

2. Access the following PIDs: 



ECT  



IAT  



RPM  

3. Verify that the engine is cold, then start the engine.  

4. Verify that the engine speed decreases as the engine warms up. 



If the engine speed does not decrease or decreases slowly, inspect the following: 



CHT sensor and related wiring harness 

(See CYLINDER HEAD TEMPERATURE (CHT) SENSOR INSPECTION [MZI-
3.7] .) 



Electronic throttle body and related wiring harness 

(See THROTTLE BODY INSPECTION [MZI-3.7] .) 

Load compensation inspection 

1. Start the engine and idle it.  

2. Connect the M-MDS to the DLC-2.  

3. Verify that P0506, P0507 is not displayed. 

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:10:06 AM

Page 104 

© 2005 Mitchell Repair Information Company, LLC. 



If P0506, P0507 are displayed, perform DTC inspection. 

(See DTC TABLE [MZI-3.7] .) 

4. Access the RPM PID. 

5. Verify that the engine speed is within the specification under each load condition. 



If load condition is not as specified, inspect the following: 



A/C switch and related wiring harness 

(See FRONT CLIMATE CONTROL UNIT INSPECTION .) 



Fan switch and related wiring harness 

(See FRONT CLIMATE CONTROL UNIT INSPECTION .) 

Throttle position (TP) sweep inspection 

1. Connect the M-MDS to the DLC-2.  

2. Turn the ignition switch to the ON position.  

3. Verify that none of the following DTC are displayed: 



P0122, P0123, P0222, P0223, P2101, P2107, P2112, P2122, P2123, P2127, P2128, P2135 



If any one DTC is displayed, perform DTC inspection.  

4. Access TP1, TP2 PID.  

5. Verify that the PID reading is within the CTP value. (See PCM INSPECTION [MZI-3.7] .) 



If the PID reading is out of range, perform the following: 



Remove the air duct from the throttle valve body.  



Verify that the throttle valve opens when the accelerator pedal is depressed. 



If the throttle valve opens, inspect the throttle position sensor and related wiring 
harness.  



If the throttle valve does not open, inspect the throttle actuator control motor and 
related wiring harness.  

6. Gradually depress the throttle pedal and verify that the PID reading increases accordingly. 



If the PID reading drops momentarily, inspect the following: 



Throttle position sensor  

7. Fully depress the throttle pedal and verify that the PID reading is within WOT value. (See PCM 

INSPECTION [MZI-3.7] .) 



If the PID reading is out of range, perform the followings: 

NOTE:



Excludes temporary idle speed drop just after the loads are turned 
on.  

 

2008 Mazda CX-9 Grand Touring 

2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9

  

Microsoft 

 

Sunday, November 15, 2009 10:10:06 AM

Page 105 

© 2005 Mitchell Repair Information Company, LLC.