Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Fuel Injector Circuit Diagnosis
2007 Chevrolet HHR L4-2.4LSECTION 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.
Circuit/System Testing
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 (w/J39021 or w/Tech 2) Fuel Injector Diagnosis (w/CH47976). Fuel Injector Diagnosis (w/J39021 or w/Tech 2) Fuel Injector Diagnosis (With CH 47976)
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
* Control Module References Programming and Relearning
* Fuel Injector Replacement
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.