Battery Voltage Out of Range
The battery voltage is outside of acceptable limits.
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 unit (ECU) expects the battery voltage to be between 9 and 16 volts while the engine is running. If the voltage drops below 9 volts or rises above 16 volts, the ECU sees this as a problem and triggers a fault code.
What the computer is actually seeing
The computer monitors the voltage from the battery through the voltage sensing circuit. If it detects values below 9V or above 16V, it sets this fault code.
What a healthy reading looks like
Expected battery voltage is between 12.6V (engine off) and 14.0-14.8V (engine 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. It should read between 12.6V to 14.8V. If it's below 12.6V, charge/test the battery.
- 22. Inspect battery connections for corrosion and tightness. Clean or tighten as necessary.
- 33. Start the engine and check the voltage again to see if it stays within normal range. If it drops below 9V or exceeds 16V, suspect the alternator.
- 44. Test the alternator's output voltage while the engine is running. It should be between 13.5V and 14.5V. If not, replace the alternator.
- 55. If voltage readings are normal, inspect wiring and connectors from the battery to the ECU for damage or disconnections.
Common causes
- Weak battery
- Faulty alternator
- Wiring issues
- Corroded battery terminals
- Faulty voltage regulator
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's generally safe to drive briefly, but you should address it soon to avoid potential battery or alternator failure.
Will this code come back after resetting?
It may come back if the underlying issue isn't fixed, like a faulty alternator or battery.
Why does this code pair with SPN 1003?
SPN 1003 indicates a low battery voltage situation, which can happen if the alternator is failing to charge the battery properly.
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 →