Voltage Too High - Aftertreatment Control Module Power Supply
This code indicates that the power supply voltage to the aftertreatment control module is too high.
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 aftertreatment control module normally gets about 10-16 volts to operate, but if it sees more than that, around 17 volts or higher, it'll throw this code.
What the computer is actually seeing
The aftertreatment control module is monitoring its supply voltage and detects a reading of 17 volts or more over a preset threshold.
What a healthy reading looks like
Normal operating voltage should be between 10.5 to 16 volts.
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. It should be between 12.4V - 12.7V when off; engine running should show 13.5V - 14.5V.
- 22. Inspect wiring and connectors to the aftertreatment control module for damage or corrosion.
- 33. Look for signs of short circuits or damaged wiring that could cause high voltage.
- 44. Check the alternator output voltage; it should be 13.5V - 14.5V when running, not exceeding 15V.
- 55. If all tests are normal, consider replacing the aftertreatment control module.
Common causes
- Faulty aftertreatment control module
- Short to power in harness
- High voltage from alternator
- Poor ground connections
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended; high voltage can cause damage to the control module, which might affect emissions.
Will this code come back if I clear it?
Yes, if the underlying issue isn't resolved, the code will return.
Why is this code related to high voltage?
Because the aftertreatment control module relies on a specific voltage range to function correctly, exceeding that indicates a 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.
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