What does it mean?
B1511 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver Belt Buckle Switch (BBS) Circuit Open Or Short To Power .
Symptoms
- Airbag warning lamp on
- Seat belt reminder chime and lamp stay on with the belt fastened, or never activate
- Driver belt pretensioner deployment logic disabled
- Fault comes and goes as the seat is slid forward and back
- Belt related warning messages in the instrument display
Likely causes
- Under-seat connector unplugged or not fully latched after cleaning, seat removal or seat covers being fitted
- Broken wire in the seat harness where it flexes through full seat travel
- Worn contacts inside the driver buckle switch, leaving the circuit permanently open
- Corroded terminal with high resistance in the buckle pigtail connector
- Buckle wiring chafed against a powered lead such as a seat heater or seat motor feed
- Foreign object such as a coin or crumbs jammed in the buckle, holding the switch off
- Airbag control module input fault after all wiring tests good
How to fix it
- Watch the buckle switch state in live data while latching and releasing the belt several times
- Check the buckle mouth for coins, food debris or a bypass clip left in the latch
- Unplug and reseat the under-seat connector, inspecting for corroded, bent or backed-out terminals
- With the buckle disconnected, measure switch resistance latched and released against specification
- Wiggle the harness through the full seat travel while watching for signal dropouts
- Repair the open or chafed harness section with proper terminals and reroute it clear of the rails
- Replace the driver buckle assembly if the switch itself is open, and only then consider the airbag control module