Functional Procedure: Unlocking

2011 BMW Alpina B7SECTION Unlocking

Pressing the Unlock button on the ID transmitter causes an encrypted remote control signal to be transmitted. The antenna in the rear window forwards the remote control signal to the diversity module. The diversity module remote control receiver demodulates, processes and then sends the signal to the Car Access System on the LIN bus.

If the vehicle is in sleep mode, the remote control receiver wakes up the Car Access System via the LIN bus for reduced-consumption operation. This allows the Car Access System to receive the request which was sent out by the ID transmitter. The ID transmitter has already been checked in the remote control receiver. If the result of the check is positive, the remote control receiver forwards the request via the LIN bus. If the request is authorized, the Car Access System wakes up the vehicle and causes the vehicle to unlock. The Car Access System thereby gives the junction box electronics module permission to unlock the central-locking drive.

The junction box electronics module then activates the relay and power output stages and triggers the unlocking of the vehicle.

NOTE: The Car Access System is responsible for communication over the LIN bus. This means that the diversity module only passes on a LIN bus signal when instructed to do so by the Car Access System 4. This applies to vehicles not currently in sleep mode.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.