What does it mean?
B2111 is a Body (airbags, seat belts, body electronics) fault code. It indicates: Manufacturer-Specific Body ECU Fault .
Symptoms
- Doors lock or unlock on their own, sometimes repeatedly
- Central locking dead from the key fob, the switch, or both
- Lock actuators buzzing or clicking without a request
- Keyless entry and remote unlock stop responding
- Alarm triggering for no reason or refusing to arm
- Battery drain because the lock motors and module stay active
Likely causes
- Chafed or broken wires inside the rubber boot between the door and the A pillar, the most common failure point
- Water inside the driver master switch or the individual door lock switch bridging contacts
- Lock switch with contacts stuck closed after a drink spill or long term corrosion
- Corroded connector at the door module or at the latch assembly
- Door latch with an integrated lock position switch that has failed shorted
- Aftermarket alarm or central locking module wired into the same circuit
- Poor body module ground raising the reference so a normal input looks like a ground
- Internal failure of the body control module input stage
How to fix it
- Confirm the manufacturer definition and the exact pin for the all door lock input
- Open the rubber boot between the door and the pillar and flex the loom while watching the input in live data
- Unplug the master switch and the individual lock switch, then measure the input circuit resistance to ground, it should read open
- If the circuit is still grounded with everything unplugged, the short is in the harness
- Check the latch connector and the door module connector for water and green corrosion
- Verify module power and ground before suspecting the module
- Repair or replace the damaged wires, using proper soldered or crimped joints and fresh insulation
- Clear the code, cycle every door and the fob, and confirm the input stays inactive at rest