Power Supply Voltage Too High
The system has detected that the power supply voltage is higher than acceptable levels.
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 truck's electronic control unit (ECU) sees that the voltage from the battery or alternator is too high, which can cause damage to various electrical components.
What the computer is actually seeing
The ECU notices voltage readings above the normal range, usually exceeding 16 volts at idle.
What a healthy reading looks like
Normal voltage should be between 12.5 to 14.8 volts when 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 the battery voltage using a multimeter. Should be between 12.5 to 14.8 volts while running.
- 22. Inspect the alternator output. If it exceeds 16 volts, it may be faulty.
- 33. Examine wiring and connectors for any signs of damage or corrosion that could cause faulty readings.
- 44. Use a scan tool to check for any additional fault codes that could indicate an underlying issue.
- 5Decision Point: If the alternator is outputting too high a voltage, replace it. If battery voltage is stable and within limits, further diagnose wiring.
Common causes
- Faulty alternator putting out too much voltage
- Bad battery causing overcharging
- Wiring issues causing incorrect readings
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's not recommended to drive long distances as high voltage can damage electronic components.
Will this code come back after clearing it?
If the underlying issue is not fixed, the code is likely to return.
Why does this code pair with SPN 0010?
Both codes can indicate issues with the power supply system, particularly involving the battery or alternator.
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 →