Vibe FWD L4-2.4L (2009)
Fuel Injector: Testing and Inspection
Fuel Injector Circuit Diagnosis
Fuel Injector Circuit Diagnosis
Diagnostic Instructions
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Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
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Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
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Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure Instructions)
provides an overview of each diagnostic category.
Circuit/System Description
The sequential fuel injection (SFI) system is controlled by the powertrain control module (PCM). Ignition voltage is supplied to the fuel injectors. The
PCM controls each fuel injector by grounding the control circuit via a solid state device called a driver. When energized the fuel injector solenoid
operates the solenoid plunger, allowing pressurized fuel to be injected into the intake port of the cylinder. The fuel pump will pressurize the fuel rail and
the fuel injectors as long as the engine is cranking and the PCM is receiving the ignition system reference pulses.
Diagnostic Aids
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Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition.
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Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition.
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If you were sent here by a DTC P0300 and all the injectors test normal, the Misfire Current Cylinder or Misfire Graphic information on a scan tool
can be used to determine which injector circuit should be examined in detail.
Reference Information
Schematic Reference
Engine Controls Schematics (See: Diagrams/Electrical Diagrams)
Connector End View Reference
Component Connector End Views (See: Diagrams/Connector Views)
Description and Operation
Fuel System Description (See: Computers and Control Systems/Description and Operation/Fuel System Description)
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions (See: Computers and Control Systems/Testing and Inspection/Diagnostic Trouble Code
Descriptions)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Special Tools
J 34730-2B Injector Test Lamp
Circuit/System Testing
Note:
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Perform this test for each fuel injector.
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If a cylinder specific misfire DTC was set, test the fuel injector of misfiring cylinder first.
1. Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition voltage circuit terminal 1 and ground.
‹› If the test lamp does not illuminate, test the ignition voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal,
test the IG2 ignition relay. Refer to Ignition Relay Diagnosis (See: Computers and Control Systems/Testing and Inspection/Component Tests
and General Diagnostics/Ignition Relay Diagnosis).
3. Ignition OFF, connect a J 34730-2B between the control circuit terminal 2 and the ignition 1 voltage circuit terminal 1.
4. Engine cranking or running, the injector test lamp should flash.
