The control module enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 44603 Injector Test Lamp

1. Ignition OFF, disconnect the harness connector at a fuel injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 1 or A and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the fuel injector.

3. Ignition OFF, connect a J 44603 between the control circuit terminal 2 or B and the ignition circuit terminal 1 or A of each fuel injector one at a time.
4. Engine cranking, the test lamp should flash for each injector.

⇒	If the test lamp is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, replace the engine control module (ECM).

⇒	If the test lamp is always OFF, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the fuel injector. Refer to Fuel Injector Diagnosis .

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

The control module enables the appropriate fuel injector pulse for each cylinder. Ignition voltage is supplied to the fuel injectors. The control module controls each fuel injector by grounding the control circuit via a solid state device called a driver.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

Special Tools

J 44603 Injector Test Lamp

1. Engine idling, observe the following control circuit status parameters for each fuel injector:

•	INJ Ckt Short Gnd Test Status

•	INJ Ckt Open Test Status

•	INJ Ckt Short Volts Test Status

•	Each parameter should display OK or Not Run.

2. Engine running, observe the DTC information with a scan tool. DTCs P0201, P0202, P0203, or P0204 should not set.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at a fuel injector.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 1 and ground.

⇒	If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition circuit fuse is open, test or replace the fuel injector.

3. Ignition OFF, connect a J 44603 Injector Test Lamp between the control circuit terminal 2 and the ignition circuit terminal 1 of each fuel injector one at a time.
4. Engine cranking, the test lamp should flash for each injector.

⇒	If the test lamp is always ON, test the appropriate control circuit for a short to ground. If the circuit tests normal, replace the engine control module (ECM).

⇒	If the test lamp is always OFF, test the appropriate control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the fuel injector. Refer to Fuel Injector Diagnosis.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.