B1318: Battery voltage low (Body Control Module)
Drive carefully. Get it checked within a week or two.
Can I drive with B1318?
Yes, but drive carefully and get it checked soon. Battery voltage dropped below operating threshold; car may not crank or accessories will turn off. Meaning can vary by make and model.
What does B1318 mean?
B1318 stands for Battery Voltage Low (BCM).
Symptoms you may notice
- Interior electrical accessory malfunction (locks, wipers, or climate buttons)
- Battery voltage warning or rapid battery drain while parked
- Key chip not recognized warning chime
How much does it cost to fix?
Repair costs for code B1318 depend on the specific underlying root cause, ranging from simple DIY checks to component replacement. The table below lists the most common causes and rough price ranges in USD:
- Weak, dying, or discharged 12V battery
- Failing alternator not maintaining charge
- Parasitic battery drain drawing power with key off
- Corroded battery cables
What to do next
- Test battery cold cranking amps and charge level.
- Check alternator charging voltage with engine running.
- Clean battery terminals and ensure clamps are snug.
Last updated: October 2026
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General guidance only, not a professional diagnosis. If the check-engine light is flashing, or the car is running rough, overheating or losing power, stop driving and get help.
About this code
Code B1318 is stored by the body controller when electrical voltage drops below 10.0 volts. It is an early warning that your battery is nearing the end of its life or your alternator is undercharging. Replace the battery before getting stranded.