Fuel Injector Circuit Diagnosis
Fuel Injector Circuit Diagnosis
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit/System Description
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.
Special Tools
J 35616-200 Test Light Probe Kit
Circuit/System Testing
1. Ignition OFF, disconnect the C104 fuel injector multi-way connector.
2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal A engine control module (ECM) harness side 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 35616-200 between the ignition circuit terminal A and the control circuit ECM harness side, of the appropriate injector listed below:
* Injector 1 terminal F
* Injector 2 terminal G
* Injector 3 terminal H
* Injector 4 terminal B
* Injector 5 terminal C
* Injector 6 terminal D
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 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. Ignition OFF, measure for 10-15 ohms on the engine harness side of C104 between the ignition circuit terminal A and the control circuit of the appropriate injector listed below:
* Injector 1 terminal F
* Injector 2 terminal G
* Injector 3 terminal H
* Injector 4 terminal B
* Injector 5 terminal C
* Injector 6 terminal D
^ If the resistance is not within the specified range, test for a short to ground or an open/high resistance between C104 and the appropriate fuel injector harness connector. If the circuits test normal, test or replace the affected fuel injector.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Fuel Injector Replacement