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Home >> Mazda >> 2012 >> CX-9 Touring, 3.7L Eng VIN V, FWD >> Repair and Diagnosis >> Engine Performance >> System >> Symptom Troubleshooting [Engine Control System MZI-3.7] >> Engine Control System Operation Inspection >> Fuel Injector Operation Inspection

Fuel Injector Operation Inspection

FUEL INJECTOR OPERATION INSPECTION CHART

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 No. 1 operation inspection.
(See Main Relay No. 1 Operation Inspection .)
Is main relay No. 1 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

Repair or replace the malfunctioning part according to the inspection results.
No Repair or replace the malfunctioning part according to the inspection results.
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.
See FUEL INJECTOR REMOVAL/INSTALLATION article.
4 Are wiring harness and connectors of not operation fuel injector normal? (Open or short) Yes Inspect PCM terminal voltage of fuel injector signal.
Repair or replace the malfunctioning part according to the inspection results.
No Repair or replace the malfunctioning part according to the inspection results.