Mazda CX-9 Grand Touring 2007 Manual page 921

2007 ENGINE PERFORMANCE Symptom Troubleshooting (MZI-3.5) - CX-9
INSPECTION [MZI-3.5] .)
If the PID reading is out of range, perform the following:
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 CHART
STEP INSPECTION
1 While cranking the engine, inspect for
fuel injector operation sound at each
cylinder using a soundscope.
Is operation sound heard?
2 Perform main relay operation
inspection.
Is main relay operation normal?
3 Switch fuel injector connector of not
operating fuel injector with operating
fuel injector.
Is operation sound heard?
4 Are wiring harness and connectors of
not 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:
2007 Mazda CX-9 Grand Touring
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 ACTION
Yes Fuel injector operation is normal.
No All cylinders not heard:
Go to the next step.
Some cylinders not heard:
Go to Step 3.
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.
Yes Go to the next step.
No Replace the fuel injector.
Yes Inspect PCM terminal voltage of fuel
injector signal.
No Repair or replace malfunctioning
parts.