Injector Circuit Malfunction - Cylinder 4
There's a problem with the fuel injector circuit for cylinder 4.
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What it means (plain English)
The computer is not getting the right signals from the fuel injector in cylinder 4. It may not be firing, or there's an issue in the wiring that connects it to the computer.
What the computer is actually seeing
The Engine Control Module (ECM) detects that the injector for cylinder 4 is not operating correctly based on voltage readings. It expects around 12V when the injector is commanded to fire and sees a lower voltage or an open circuit.
What a healthy reading looks like
When the engine is running, the fuel injector should show a voltage close to 12V when activated, and resistance values should range between 12 to 16 ohms for proper operation.
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect wiring and connectors to the injector for damage or corrosion; repair as needed.
- 22. Use a multimeter to check the resistance of the injector; it should be between 12-16 ohms. If it's out of range, replace the injector.
- 33. Check for proper voltage at the injector connector; you should see 12V when the engine is cranking or running. If not, the issue may be in the wiring or ECM.
- 44. If the injector tests OK but the problem persists, consider backprobing the ECM connector to ensure the signal wire is functioning.
Common causes
- Faulty fuel injector
- Open or shorted wiring in the injector circuit
- Bad connector or corrosion
- Faulty Engine Control Module (ECM)
- Low fuel pressure affecting injector operation
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's drivable but fix soon. Running on three cylinders can cause engine damage or catalyst issues.
Will this code come back after clearing?
If the underlying issue isn’t fixed, yes, the code will likely return.
Why does this code appear with others like P0206?
They indicate injector circuit problems on multiple cylinders, often due to wiring issues or shared components.
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