Crash unlocking
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2017 BMW X3, 2016 BMW X3, 2015 BMW X3, 2014 BMW X3, and 2013 BMW X3. However, it is still accessible from the selected car via links, so may be relevant.
A crash is detected by the ACSM safety system (ACSM stands for "Advanced Crash Safety Module", referred to as the "crash safety module"). The crash safety module (ACSM) sends a crash signal on a bus connection to the front electronic module (FEM). The front electronic module outputs the request to unlock the vehicle on a bus connection.
The front electronic module (FEM) activates the central locking system. All operating points are disabled when there is a crash message. This prevents unintentional actions of the central locking system from occurring due to line short circuits caused by the accident. The central locking system can only be reactivated after a crash once terminal R has been switched off for at least 3 seconds.