Procedure after airbag deployment as result of an accident (M4 2021-2023)

Replace the components involved in the accident, check all others! 

Check and/or replace following components after airbag deployment:

• Components
  • Sensor B-pillar (left/right)
  • Sensor front door (left/right)
  • Sensor seat, Driver-/passenger's side
  • Airbag control unit, vehicle interior
  • Sensor, pedestrian protection
  • Front sensor (engine compartment)
• Procedure

• Inspect visually for mechanical damage (housing, plug connections). Replace damaged components.
• Connect BMW diagnostic system
• Read fault memory
• Disconnect the vehicle battery and adhere to the waiting period (at least 30 seconds)
• Rectify faults
• Reconnect the vehicle battery and adhere to the waiting period (at least 10 seconds)
• Delete fault memory
• Switch off ignition and wait at least 2 minutes (no consumers may be switched on during this period such as interior light, radio, etc.)
• Switch the ignition on (wait for at least 10 seconds)
• Delete fault memory
• If you cannot delete the fault memory: Replace the component that is causing the fault

Replace airbag control unit only in the following cases: 

• In the case of visible external damage
• In the case of a corresponding fault memory entry (airbag checklight is illuminated)

Cables and connectors 

• Components and procedure

• Check cables and connectors for damage, replace if necessary.

(e.g. corrosion, correct engagement, bent pin)

Seat belt system 

• Components
  • Electrically motorized reel
  • Seat belt tensioner
  • Seat belt height adjustment
  • end fitting pretensioner
  • seat belt buckle
• Procedure

• Check components, replace if necessary
• Additional door lock: Check for foreign body, remove it if necessary.

Seats 

• Components
  • Seat
  • Airbag module
  • Active head restraint
• Procedure

• Check seats (functional check of seat mechanism), replace if necessary
• Check seat connection
• Replace gas generator of active head restraint

  If the accident severity has not caused any other damage to the seat, only the gas generator that has tripped needs to be replaced.

  External feature: The released head restraint is folded forward and locked in place.

  The repair can be carried out in the vehicle with the rear panel removed. The entire system can be pushed back to its original position and the new gas generator can be inserted.

  The gas generator can be replaced up to 5 times.

• Replace airbag module and seat cover with upholstery

Driver's airbag 

• Components
  • Airbag module
  • Steering wheel
  • Steering column (if damaged)
  • Steering wheel cover
  • Steering-wheel switch
  • Shift paddle for automatic transmission
  • Wiring harness
• Procedure

• Check components for damage, replace if necessary
• Replace steering wheel
• Only for the M Sport steering wheel: Replacing impact plate

Front passenger airbag 

• Components
  • Airbag module
  • Dashboard trim panel (must be replaced!)
  • Supporting tube (if damaged)
• Procedure

• Check components, replace if necessary

Side airbag, front/rear 

• Components
  • Airbag module
  • Door trim panel
  • Door in white
  • Seat
• Procedure

• Check components; replace if necessary

Head airbag 

• Components
  • Airbag module
  • A-pillar trim panel
  • Headliner
  • Cover, B-pillar (if damaged)
  • C-pillar trim panel (if damaged)
  • Connection/mount (on side frame)
• Procedure

• Check components, replace if necessary

Knee airbag 

• Components
  • Trim panel (driver's side)
  • Lower part of glove compartment
  • Knee protection (Driver- and passenger's side)
• Procedure

• Check components, replace if necessary

Passive knee protection 

• Components
  • Trim panel (driver's side)
  • Glove compartment incl. knee protection (passenger's side)
• Procedure

• Check components for damage, replace if necessary
• Check retaining elements