Faulty Fuel Injector Signal
This code indicates an issue with the fuel injector signal for an injector circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The engine's computer is not getting the right signals from one of the fuel injectors, which can cause misfires or reduced performance.
What the computer is actually seeing
The engine control module (ECM) monitors the fuel injector signal for proper voltage and timing. It expects a pulse signal between 0.5 to 4.0 milliseconds based on engine speed and load.
What a healthy reading looks like
Injector pulse width should be around 1.0 to 3.0 milliseconds at idle, with voltage levels near 12V when active.
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. Check the fuel injector wiring for breaks or shorts; repair or replace as needed. Decision: Was wiring okay? If NO, fix wiring.
- 22. Test the fuel injector connector for proper voltage using a multimeter; should read around 12V when active. Decision: Is voltage present? If NO, check circuit back to ECM.
- 33. Swap the suspected faulty injector with a known good injector; clear the code and run a test. Decision: Did the problem follow the injector? If YES, replace the injector.
- 44. If the issue persists, consider scanning for ECM updates or faults; if no updates available, the ECM may be faulty.
Common causes
- Faulty fuel injector
- Wiring issues in injector circuit
- Bad ECM
- Poor electrical connections or corrosion
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderately severe—it's best to fix it soon to avoid further damage.
Will this issue come back after fixing?
If the root cause is addressed correctly, it should not return.
Why does it pair with SPN 191?
SPN 191 is often related to injector performance, so they can indicate multiple issues with injector circuits.
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