Control Unit: Notes

The VDM control unit is located in the passenger compartment near the right-hand A-pillar. The VDM control unit receives its power supply via Terminal 15N and is protected by a 5A fuse. The VDM control unit is activated exclusively by the Car Access System (CAS) via a Terminal 15N lead as of status "Ignition ON".

Fig 1: Identifying VDM Control Unit Location

Courtesy of BMW OF NORTH AMERICA, INC.

A vehicle authentication process takes place when the system is started. This compares the vehicle identification number from the CAS with the vehicle identification number which is encoded on the VDM control unit.

That is followed by a check of the VDM control unit's hardware and software. All outputs (valve solenoids and sensors) are subjected to a comprehensive check for short circuits and circuit breaks. If there is a fault, the system switches the actuators to a safe-driving mode.

The VDM control unit switches off if the voltage is too low/too high.