Engine Control Module (ECM) Power Supply Voltage
The ECM is detecting a power supply voltage 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 Engine Control Module isn't getting enough power to do its job properly, which can cause performance issues or prevent the engine from starting.
What the computer is actually seeing
The ECM expects a steady voltage between 10 and 16 volts. If the voltage drops below 9 volts or goes above 17 volts, it sets this fault code.
What a healthy reading looks like
Normal supply voltage should be between 10 and 16 volts with less than 0.5 volts ripple.
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.
- 1Check battery voltage; should be between 10 and 16 volts.
- 2Inspect battery terminals and wiring for corrosion or damage.
- 3Test the alternator output; it should produce around 14 volts with the engine running.
- 4Ensure ground connections to the ECM are clean and secure.
- 5Use a multimeter to check for voltage drop in the power supply circuit.
Common causes
- Faulty battery
- Corroded connections
- Bad ground connections
- Failed alternator
- Wiring harness issues
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
No, it can lead to engine stalling or no-start conditions.
Will the code come back after resetting it?
If the underlying issue isn't fixed, yes, it will return.
What happens if I ignore this code?
Ignoring it can cause further electrical problems and affect engine performance.
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