4. Central locking system
WARNING: This page is about a different car, the 2009 Saab 9-3. However, it is still accessible from the selected car via links, so may be relevant.
The BCM contains all the logic for the central locking system. When you press the remote control to unlock the car, the MIU receives a radio message. The MIU wakes the other control modules on the I-bus and informs of which button was pressed and how (e.g. single press). The BCM sends an unlock command over the bus, at which the four door modules (DDM, PDM, RRDM and RLDM) unlock their respective doors. The REC unlocks the boot lid and the BCM unlocks the fuel filler flap.
4D
CV
The BCM contains the central locking logic and can be programmed to unlock only the driver's door and fuel filler flap if the unlock button is only pressed once.