ECM/PCM Power Input Signal
Indicates a problem with the ECM/PCM power supply.
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 Control Module (ECM) isn't getting the correct voltage it needs, which could stop it from working properly.
What the computer is actually seeing
ECM is expecting around 12-14 volts when the vehicle is running. If it sees less than 11.5 volts, it sets this code.
What a healthy reading looks like
12-14 volts for normal operation; below 11.5 volts triggers a fault.
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 battery voltage; it should be above 12.4 volts with the engine off.
- 22. Inspect battery terminals and cables for corrosion or loose connections; repair as necessary.
- 33. With the engine running, measure the voltage at the ECM power input pin; it should be 12-14 volts.
- 44. If voltage is low while running, check the alternator output. It should be around 13.5-14.5 volts at the battery terminals.
- 55. Verify continuity and inspect for shorts or open circuits in the harness between the alternator and ECM.
- 66. If all power supplies are good, consider replacing the ECM as a last resort.
Common causes
- Poor battery condition
- Faulty wiring or corroded connectors
- Weak or faulty alternator
- Blown fuses in the power circuit
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive for long; reduced power or stalling may occur.
Will this code come back after clearing it?
If the underlying issue isn't fixed, yes, it will return.
Why does this code appear with others?
It often pairs with other power supply issues, indicating a broader electrical problem.
Working a real vehicle right now?
Let DiagCoach walk you through it live with your specific symptoms, vehicle, and what you've already checked.
Start guided diagnostic →