What does it mean?
B1512 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Driver Belt Buckle Switch (BBS) Circuit Short To Ground .
Symptoms
- Airbag warning lamp on
- Seat belt reminder behaves as if the belt is always fastened, or always unfastened
- Chime does not sound when driving off unbelted
- Code returns immediately after clearing because the short is permanent
- Belt status shown in scan data does not change when latching the belt
Likely causes
- Buckle wiring chafed against the seat frame or rail where it moves with the seat
- Liquid spilled into the buckle, leaving conductive residue across the switch contacts
- Terminal pushed out of the under-seat connector and touching the seat structure
- Wire crushed under a seat mounting bolt when the seat was refitted
- Internal short inside the buckle switch after long service or water ingress
- Corrosion in the connector from a floor leak or a wet carpet
How to fix it
- Watch belt status in live data while latching and releasing; a value that never changes confirms the short
- Unplug the buckle and measure the harness side to ground with the connector separated
- Inspect the buckle body for spilled drinks and clean or replace it if residue is found in the switch
- Follow the harness along the seat rails looking for chafe, crush points and trapped wiring
- Check the connector for terminals contacting the seat frame and for corrosion from a wet carpet
- Repair the shorted wiring with proper terminals and secure it clear of moving metal
- Replace the driver buckle assembly if the short is inside the switch, then clear and verify