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Home › Mazda › 2012 › CX-7 i Touring, 2.5L Eng VIN 5 › Repair and Diagnosis › Engine Performance › System › Symptom Troubleshooting [Engine Control System 2.5L L5] › Engine Control System Operation Inspection › Fuel Injector Operation Inspection

Fuel Injector Operation Inspection

If simulation function of M-MDS is used: 

STEP INSPECTION RESULTS ACTION
1 Start the engine and warm it up until normal operating temperature.
Access the INJ#1, INJ#2, INJ#3 and INJ#4 PIDs using the M-MDS.
(See ON-BOARD DIAGNOSTIC TEST .)
Turn the fuel injector from on to off using the PIDs each cylinder.
Does the engine speed drop?		 Yes Fuel injector work properly.
No Go to the next step.
2 Disconnect the fuel injector that the engine speed does not drop at Step 1.
Turn the ignition switch to the ON position (engine off).
Measure the voltage between suspect fuel injector terminal B (wiring harness-side) and body ground.
Is the voltage B+  ?		 Yes Go to the next step.
No Repair or replace for a possible open or short circuit.
3 Inspect for open or short circuit in wiring harness between suspect fuel injector terminal A (wiring harness-side) and following PCM terminals (wiring harness-side):
  • Fuel injector No.1
    • PCM terminal 2BB
  • Fuel injector No.2
    • PCM terminal 2BC
  • Fuel injector No.3
    • PCM terminal 2BD
  • Fuel injector No.4
    • PCM terminal 2AZ

Is there any malfunction?		 Yes Repair or replace for a possible open or short circuit.
No Go to the next step.
4 Inspect suspect fuel injector.
(See FUEL INJECTOR INSPECTION .)
Is there any malfunction?		 Yes Replace the fuel injector.
(See FUEL INJECTOR REMOVAL/INSTALLATION .)
No Replace the PCM.
(See PCM REMOVAL/INSTALLATION .)

If simulation function of M-MDS is used: 

STEP INSPECTION RESULTS ACTION
1 While cranking engine, inspect for fuel injector operation sound at each cylinder using a soundscope.
Is operation sound heard?		 Yes Fuel injector work properly.
No Go to the next step.
2 Disconnect the fuel injector that the engine speed does not drop at Step 1.
Turn the ignition switch to the ON position (engine off).
Measure the voltage between suspect fuel injector terminal B (wiring harness-side) and body ground.
Is the voltage B+  ?		 Yes Go to the next step.
No Repair or replace for a possible open or short circuit.
3 Inspect for open or short circuit in wiring harness between suspect fuel injector terminal A and following PCM terminals:
  • Fuel injector No.1
    • PCM terminal 2BB
  • Fuel injector No.2
    • PCM terminal 2BC
  • Fuel injector No.3
    • PCM terminal 2BD
  • Fuel injector No.4
    • PCM terminal 2AZ
 Yes Repair or replace for a possible open or short circuit.
No Go to the next step.
4 Inspect suspect fuel injector.
(See FUEL INJECTOR INSPECTION .)
Is there any malfunction?		 Yes Replace the fuel injector.
(See FUEL INJECTOR REMOVAL/INSTALLATION .)
No Replace the PCM.
(See PCM REMOVAL/INSTALLATION .)
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