Mazda CX-9 Grand Touring. Manual — part 348

3. Access PIDs for the switch you are inspecting.

4. Vibrate the sensor slightly with your finger.



If PID value is unstable or malfunction occurs, check for poor connection or poorly mounted sensor
or both.

Inspection Method for Actuators or Relays

1. Connect the M-MDS to the DLC-2.

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

3. Prepare the output state control function for actuators or relays that you are inspecting.

4. Vibrate the actuator or relay with your finger for 3 s after output state control function is activated.



If variable click sound is heard, check for poor connection or poorly mounted actuator or both, or
the relay.

WATER SPRINKLING METHOD

If malfunction occurs only under high humidity or rainy/snowy weather, perform the following steps:

1. Connect the M-MDS to the DLC-2 if you are inspecting sensors or switches.

NOTE:



If the engine starts and runs, perform the following steps during idle.

NOTE:



Vibrating relays too strongly may result in open relays.

Fig. 11: Inspection Method For Relays
Courtesy of MAZDA MOTORS CORP.

CAUTION:



Indirectly change the temperature and humidity by spraying water
onto the front of the radiator.



If a vehicle is subject to water leakage, the leakage may damage the
control module. When testing a vehicle with a water leakage problem,
special caution must be used.

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 98

© 2005 Mitchell Repair Information Company, LLC.

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

3. Access PIDs for sensor or switch if you are inspecting sensors or switches.

4. If you are inspecting the switch, turn it on manually.

5. Spray water onto the vehicle or run it through a car wash.



If PID value is unstable or malfunction occurs, repair or replace part if necessary.

Fig. 12: Water Sprinkling Method
Courtesy of MAZDA MOTORS CORP.

ENGINE CONTROL SYSTEM OPERATION INSPECTION [MZI-3.7]

INPUT SIGNAL SYSTEM INSPECTION PROCEDURE

1. Find an irregular signal. (See FINDING IRREGULAR SIGNALS.)

2. Locate source. (See LOCATING THE SOURCE OF UNUSUAL SIGNALS.)

3. Repair or replace the malfunctioning part.

4. Confirm that the irregular signal is no longer detected.

Finding irregular signals

While referring to, use the PID/DATA monitor and record function to inspect the input signal system relating to
the problem.

1. Start the engine and idle the vehicle. You can assume that any signals that are out of specification by a

wide margin are irregular.

2. When recreating the problem, any sudden change in monitor input signals that is not intentionally created

by the driver can be determined as irregular.

Locating the source of unusual signals

NOTE:



If the engine starts and runs, perform the following steps at idle.

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 99

© 2005 Mitchell Repair Information Company, LLC.

Variable resistance type 1 (TP sensor)

Fig. 13: Variable Resistance Type 1 (TP Sensor)
Courtesy of MAZDA MOTORS CORP.

Input signal system inspection for variable resistance type 1

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 for the following points concerning the
sensor connector:



Female terminal opening is loose.



Coupler (pin holder) damage

CAUTION:



Compare the M-MDS monitor voltage with the measurement voltage
using the digital measurement system function. If you use another
tester, misreading may occur.



When measuring voltage, attach the tester GND to the GND of the
PCM that is being tested, or to the engine itself. If this is not
performed, the measured voltage and actual voltage may differ.



After connecting the pin to a waterproof coupler, confirming
continuity and measuring the voltage, inspect the waterproof
connector for cracks. If there are any, use sealant to fix them. Failure
to do this may result in deterioration of the wiring harness or terminal
from water damage, leading to problems with the vehicle.

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 100

© 2005 Mitchell Repair Information Company, LLC.



Pin discoloration (blackness)



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

Standard power supply system inspection for variable resistance type 1



Confirm that the #3 terminal is at 5 V.



If the measured voltage on the #3 terminal is 5 V , 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



Pin discoloration (blackness)



If the #3 terminal measures other than 5 V , inspect for the following:



Open or short circuit in wiring harness



Harness/pin crimp is loose or disconnected.

GND system inspection for variable resistance type 1



Confirm that terminal sensor #5 is at 0 V.



If it is at 0 V , inspect the sensor.



If necessary, replace the sensor.



If not, inspect for the following:



Open or short circuit in wiring harness



Female terminal opening is loose causing an open or short circuit in wiring harness



Coupler (pin holder) damage



Pin discoloration (blackness)



Harness/pin crimp is loose or disconnected.

Variable resistance type 2 (mass air flow (MAF) sensor & VSS)

Fig. 14: Variable Resistance Type 2 (Mass Air Flow Sensor & VSS)
Courtesy of MAZDA MOTORS CORP.

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 101

© 2005 Mitchell Repair Information Company, LLC.