Mazda CX-9 Grand Touring. Manual — part 350



Remove the air duct from throttle valve body.



Verify that the throttle valve opens when throttle 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.

FUEL INJECTOR OPERATION INSPECTION

FUEL INJECTOR OPERATION INSPECTION CHART

FUEL CUT CONTROL SYSTEM INSPECTION

If simulation function of the M-MDS is used:

1. Warm up the engine and idle it.

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

3. Select the RPM and FUELSYS1 PIDs.

STEP

INSPECTION

RESULTS

ACTION

1

While cranking the engine, inspect for fuel
injector operation sound at each cylinder using a
soundscope.
Is operation sound heard?

Yes

Fuel injector operation is normal.

No

All cylinders not heard:

Go to the next step.

Some cylinders not heard:

Go to Step 3.

2

Perform main relay operation inspection.
Is main relay operation normal?

Yes

Inspect the following:



Fuel injector power system
related wiring harness and
connectors



PCM connectors



Fuel injector GND and related
wiring harness and connectors

No

Repair or replace malfunctioning

parts.

3

Switch fuel injector connector of not operating
fuel injector with operating fuel injector.
Is operation sound heard?

Yes

Go to the next step.

No

Replace the fuel injector.

4

Are wiring harness and connectors of not
operation fuel injector normal? (Open or short)

Yes

Inspect PCM terminal voltage of fuel
injector signal.

No

Repair or replace malfunctioning

parts.

NOTE:



This inspection has to perform after the Fuel Injector Operation Inspection.

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 106

© 2005 Mitchell Repair Information Company, LLC.

4. Monitor the both PIDs while performing the following steps.

1. Depress the accelerator pedal and increase the RPM PID to 4,000 rpm.

2. Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the FUELSYS1

PID is OL, and CL. when the RPM PID drops below 1,200 rpm.



If not as specified, inspect the following.



CHT sensor and related harness

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



TR switch and related wiring harness

(See TRANSAXLE RANGE (TR) SWITCH INSPECTION [AW6A-EL, AW6AX-
EL] .)

If simulation function of the M-MDS is not used:

1. Warm up the engine and idle it.

2. Measure the fuel injector control signal wave profile using the oscilloscope while performing the

following steps.

1. Depress the accelerator pedal and increase the engine speed to 4,000 rpm.

2. Quickly release the accelerator pedal (brake pedal is not depressed) and verify that the wave profile

constant B+ , and appears wave, when the engine speed drops below 2,200 rpm.



If not as specified, inspect the following.



CHT sensor and related harness

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



TR switch and related wiring harness

(See TRANSAXLE RANGE (TR) SWITCH INSPECTION [AW6A-EL, AW6AX-
EL] .)

FUEL PUMP OPERATION INSPECTION

1. Remove the fuel-filler cap.

2. Turn the ignition switch to the ON position.

3. Turn the fuel pump relay from off to on using the FP PID and inspect if the operation sound is heard.



If no operation sounds is heard, proceed to next step.

4. Measure voltage at wiring harness side fuel pump connector terminal B.

Specification

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 107

© 2005 Mitchell Repair Information Company, LLC.

B+ (Ignition switch at on)



If the voltage is as specified, inspect the following:



Fuel pump continuity



Fuel pump GND



Wiring harness between fuel pump relay and PCM terminal 1V



If not as specified, inspect the following:



Fuel pump relay



Wiring harness connector (Main relay-fuel pump relay-fuel pump)

FUEL PUMP CONTROL SYSTEM INSPECTION

1. Crank the engine and verify that fuel pump relay operation sound is heard.

2. If operation sound is not heard, inspect the following:



Fuel pump relay

(See RELAY INSPECTION .)



Wiring harness and connectors (Main relay-fuel pump relay-PCM terminal 1V)

SPARK TEST

1. Disconnect the fuel pump relay.

2. Verify that each ignition coil and connector is connected properly.

3. Inspect the ignition system in the following procedure.

FUEL PUMP CONTROL SYSTEM INSPECTION CHART

WARNING:



High voltage in the ignition system can cause strong electrical
shock which can result in serious injury. Avoid direct contact
to the vehicle body during the following spark test.

STEP

INSPECTION

ACTION

1



Disconnect the ignition coil from the
spark plugs.



Remove the spark plugs.



Ensure that the spark plugs don't
have carbon deposits.



Are the spark plugs OK?

Yes Go to the next step.

No

Perform 2 times of no-load racing at 4000

rpm for 2 min to burn off the carbon deposits.

Then repeat this step.

2



Inspect the spark plugs for damage, wear,
and proper plug gap.



Are the spark plugs normal?

Yes Go to the next step.

No Replace spark plugs, then go to the next step.

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 108

© 2005 Mitchell Repair Information Company, LLC.

PURGE CONTROL SYSTEM INSPECTION

If simulation function of the M-MDS is used:

1. Start the engine.

3



Reconnect the spark plugs to the ignition
coil.



Ground the spark plugs to the engine.



Is a strong blue spark visible at each
cylinder while cranking?

Yes Ignition system is normal.

No

Some cylinders do not spark:



Go to the next step.

All cylinders do not spark:



Go to Step 5.

4



Inspect the following wiring harnesses
for open or short:



Ignition coil No.1 terminal C-PCM
terminal 2A



Ignition coil No.2 terminal C-PCM
terminal 2F



Ignition coil No.3 terminal C-PCM
terminal 2K



Ignition coil No.4 terminal C-PCM
terminal 2W



Ignition coil No.5 terminal C-PCM
terminal 2AA



Ignition coil No.6 terminal C-PCM
terminal 2AE



Are the wiring harnesses normal?

Yes

Inspect and replace the ignition coil.
(See IGNITION COIL INSPECTION
[MZI-3.7] .)

No

Repair or replace the malfunctioning part,

then go to Step 1.

5



Measure the voltage at terminal A in each
ignition coils.



Is the voltage B+?

Yes Go to the next step.

No Inspect power supply circuit of ignition coils.

6

Verify continuity between each ignition coils
terminal B and battery negative post.
Is there any continuity?

Yes Go to the next step.

No

Inspect GND circuit of ignition coils.

7



Does the PCM connector or ignition coil
connectors have poor connection?

Yes

Repair or replace the connector, then go to
Step 1.

No

Go to the next step.

8



Are the following parts normal?



CKP sensor and crankshaft pulley

Yes

Inspect for open or short circuit in wiring
harness and connector of CKP sensor.

No

Repair or replace the malfunctioning part,

then go to Step 1.

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 109

© 2005 Mitchell Repair Information Company, LLC.