Fuel Cut Control System Inspection - Mazda 3 Workshop Manual

Mazda 3 Workshop Manual – Engine + Wiring Diagrams + Diagnostic Trouble Codes
While cranking engine, inspect for fuel injector
operation sound at each cylinder using a
soundscope.
Is operation sound heard?
Perform the main relay operation inspection.
2
Is main relay operation normal?
Change fuel injector connector of not operating
fuel injector and operating fuel injector.
3
Is operation sound heard?
Are wiring harness and connectors of not
4 operation fuel injector normal? (Open or short
circuit)

Fuel Cut Control System Inspection

1. Warm-up engine and idle it.
2. Turn off the electrical loads and A/C switch.
3. Connect WDS or equivalent to the DLC-2.
4. Access RPM and FUELPW PIDs.
5. Monitor both PIDs while performing the following steps.
(1) Depress the accelerator pedal and increase the engine speed to 4,000 rpm.
(2) Release the accelerator pedal (brake pedal is not depressed) and verify that the fuel injector
duration time is 0 ms, and 2-5 ms when the engine speed drops 1,200 rpm or less.
• If not as specified, inspect the following.
- ECT sensor and related wiring harness (See
SENSOR INSPECTION
- Neutral/clutch pedal position switch and related wiring harness (MTX) (See
POSITION (CPP) SWITCH INSPECTION
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All cylinders no heard:
Go to the next step.
No
Some cylinders no heard:
Go to Step 3.
Inspect the following:
• Fuel injector power system related
wiring harness and connectors
Yes
• PCM connectors
• Fuel injector GND and related
wiring harness and connectors
Repair or replace the
No
malfunctioning part.
Yes Go to the next step.
Replace fuel injector.
No
Fuel pump relay (See
INJECTOR
Inspect the PCM terminal voltage of
Yes
fuel injector signal.
Repair or replace the
No
malfunctioning part.
ENGINE COOLANT TEMPERATURE (ECT)
- automotive repair manuals website
FUEL
INSPECTION.)
CLUTCH PEDAL