Diagnostic Instructions
Circuit/System Description
The sequential multiport 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
| • | Monitoring the misfire current counters, or misfire graph, may help to isolate the fuel injector that is causing the condition. |
| • | Operating the vehicle over a wide temperature range may help isolate the fuel injector that is causing the condition. |
| • | 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
Connector End View Reference
Component Connector End Views
Description and Operation
Fuel System Description
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References for scan tool information
Special Tools
J 34730-2B
Injector Test Lamp
Circuit/System Testing
Important:
| • | Perform this test for each fuel injector. |
| • | If a cylinder specific misfire DTC was set, test the fuel injector of misfiring cylinder first. |
- Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
- Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit terminal 1 and ground.
| ⇒ | If the test lamp does not illuminate, test the ignition 1 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. |
- Ignition OFF, connect a
J 34730-2B
between the control circuit terminal 2 and the ignition 1 voltage circuit terminal 1.
- Engine cranking or running, the injector test lamp should flash.
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If circuit tests normal, replace the PCM. |
| ⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the PCM. |
- If all circuits test normal, test or replace the fuel injector.
Component Testing
- Ignition OFF, disconnect the harness connector at the appropriate fuel injector.
Important: The engine coolant temperature (ECT) sensor must be between 19-21°C (64-72°F) in order for an accurate measurement.
- Test for 11.4-12.6 ohms between the ignition 1 voltage terminal 1 and the control terminal 2.
| ⇒ | If not within the specified range, replace the fuel injector. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic procedure.
