B1318 Code: Battery Voltage Low
🟠 Moderate severity · drivable
Drivable short-term, but low voltage can cause stalling and electrical faults. Diagnose the battery and charging system soon.
What B1318 means
The body control module is seeing battery voltage that's too low, usually below about 10 volts. This points to a battery or charging problem.
Symptoms
- Check engine light or battery light on
- Hard or slow cranking
- Dim lights
- Electrical accessories acting up
Common causes
- most common: Weak or failing battery
- common: Failing alternator
- common: Loose or corroded battery terminals
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Clean and tighten the battery terminals | Yes | $0–20 |
| Test the battery and replace it if weak | Yes | $100–250 |
| Test the alternator and replace it if failing | Mechanic | $200–500 |
Frequently asked questions
Can I drive with a B1318 code?
Short distances, yes, but the car could stall or fail to start. Get the battery and charging system tested soon.
What is the most common cause of B1318?
A weak battery or failing alternator.
How much does it cost to fix a B1318?
A battery is $100–$250; an alternator is $200–$500 installed.
Related codes
B1317
B1317 Code: Battery Voltage High
P0562P0562 Code: System Voltage Low
P0560P0560 Code: System Voltage Malfunction
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.