Battery Voltage High
The system has detected a battery voltage that is higher than expected.
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)
Your vehicle's computer is seeing a voltage level from the battery that’s above normal range, which could cause problems with electrical components.
What the computer is actually seeing
The Battery Control Module (BCM) sees a constant voltage reading above 15 volts for a specified duration (typically over 30 seconds).
What a healthy reading looks like
Normal battery voltage is 12.6 to 14.4 volts when the engine is running. If it reads over 15 volts, this code tends to trigger.
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. Perform a visual inspection of the battery and alternator connections. Look for corrosion, loose terminals, or damaged wires. If found, repair these issues first.
- 22. Use a multimeter to check the battery voltage with the engine off, it should be around 12.6 volts. If it’s much higher, check the battery health.
- 33. Start the engine and measure the voltage at the battery terminals again; it should be between 13.5 and 14.5 volts. If it’s over 15 volts, suspect the voltage regulator or alternator.
- 44. If the alternator is producing too high a voltage, replace it and clear the codes to see if the issue returns.
Common causes
- Faulty voltage regulator
- Bad battery
- Corroded connections at the battery
- Faulty alternator
- Wiring issues causing feedback
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It may be drivable, but if the battery voltage is too high, it can damage electrical components, so fix it soon.
What happens if I ignore this code?
Ignoring it can lead to electrical failures, battery damage, and eventually vehicle breakdown.
Why did this code pair with B1986?
B1986 indicates a low battery voltage, while B1987 indicates high voltage. They can occur due to a failing alternator or battery behavior.
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