Battery Voltage High
The battery voltage is abnormally high, indicating a possible charging system 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 car's computer is seeing a battery voltage over 16 volts, which usually means the alternator is overcharging.
What the computer is actually seeing
The vehicle's computer monitors battery voltage. It sees a reading above 16 volts for a specified period, triggering the B1302 code.
What a healthy reading looks like
Normal battery voltage should be between 12.6 to 14.4 volts during running conditions.
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 while the engine is off. Expected value: 12.6-12.8 volts. If above 12.8 volts, charge or replace the battery.
- 22. Start the engine and check battery voltage again. Expected value: 13.5-14.4 volts. If above 14.4 volts, proceed to the next step.
- 33. Measure the voltage at the alternator output terminal while the engine is running. Expected value: same as battery voltage if in good condition. If much higher, replace the alternator.
- 44. Inspect the voltage regulator if the alternator checks out. Ensure it's properly grounded and connected. Repair or replace as necessary.
- 55. Check all related wiring and connections for damage or corrosion. Repair any issues found.
Common causes
- Faulty alternator
- Bad voltage regulator
- Wiring issues in the charging circuit
- Corroded battery terminals
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code on?
It's not recommended to drive if the battery voltage is excessively high, as it can damage electronic components.
Will this code come back after I clear it?
If the underlying issue isn't fixed, the code will return after a short time.
Could a dead battery cause this code?
No, a dead battery typically causes a low voltage code. This code indicates high voltage issues.
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 →