ECM/PCM Power Supply Voltage
The Engine Control Module (ECM) detected a voltage supply issue.
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 ECM needs a steady power supply of 10-16 volts to function properly, and it's currently getting something outside that range, likely due to a wiring or connector issue.
What the computer is actually seeing
The ECM monitors its own voltage supply through internal circuits and expects it to maintain a stable range of 10-16 volts. Any significant drop below or spike above results in the fault code being triggered.
What a healthy reading looks like
ECM voltage supply should be between 10.0 to 16.0 volts while the engine is running.
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 battery voltage with a multimeter. Voltage should be between 12.4V and 12.7V for a healthy battery at rest.
- 22. Inspect all wiring and connectors to the ECM for corrosion, damage, or poor connections. Fix any issues found.
- 33. Start the engine and re-check the voltage at the ECM connector. It should still maintain between 10-16 volts with the engine running.
- 44. If voltage is low or erratic, check the output of the alternator. It should be around 13.8 to 14.5 volts while running. Test the alternator and replace if faulty.
- 55. If everything checks out but the code persists, consider checking the ECM itself for faults. Use a scan tool to look for other related error codes.
Common causes
- Bad wiring or connectors supplying power to the ECM.
- Weak or failing battery.
- Faulty alternator causing voltage spikes or drops.
- Short circuit or grounding issues in the ECM power circuit.
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's moderately severe, so you should fix it soon as it could affect engine performance.
Will the code come back after clearing it?
If the underlying issue isn't fixed, yes, it will likely return.
Why does this code sometimes appear with other codes?
It often pairs with other voltage-related codes, indicating a systemic power supply issue.
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