Mazda CX-9 Grand Touring 2009 Manual page 1397

Remove the air duct from throttle valve body.
Verify that the throttle valve opens when throttle pedal is depressed.
FUEL INJECTOR OPERATION INSPECTION
FUEL INJECTOR OPERATION INSPECTION CHART
STEP INSPECTION
While cranking the engine, inspect for fuel
injector operation sound at each cylinder using a
1
soundscope.
Is operation sound heard?
Perform main relay operation inspection.
2
Is main relay operation normal?
Switch fuel injector connector of not operating
3 fuel injector with operating fuel injector.
Is operation sound heard?
Are wiring harness and connectors of not
4
operation fuel injector normal? (Open or short)
FUEL CUT CONTROL SYSTEM INSPECTION
NOTE:
This inspection has to perform after the Fuel Injector Operation 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.
2008 Mazda CX-9 Grand Touring
2008 ENGINE Symptom Troubleshooting (MZI-3.7) - Mazda CX-9
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.
RESULTS
Yes Fuel injector operation is normal.
All cylinders not heard:
Go to the next step.
No
Some cylinders not heard:
Inspect the following:
Fuel injector power system
related wiring harness and
Yes
connectors
PCM connectors
Fuel injector GND and related
wiring harness and connectors
Repair or replace malfunctioning
No
Yes Go to the next step.
No Replace the fuel injector.
Inspect PCM terminal voltage of fuel
Yes
injector signal.
Repair or replace malfunctioning
No
ACTION
Go to Step 3.
parts.
parts.