Central Locking System Circuit Diagram

Fig 1: Central Locking System Circuit Diagram

Courtesy of BMW OF NORTH AMERICA, INC.

COMPONENTS DESCRIPTION CHART

Index	Explanation
1	Footwell module (FRM)
2	Car Access System (CAS)
3	Center-lock button
4	Junction box electronics module (JB)
5	Front-passenger-door illuminated entry system
6	Door contact, central locking, front passenger door
7	Rear, passenger-side illuminated entry system
8	Door contact, central locking, rear passenger side
9	Fuse in the luggage compartment power distribution box
10	Central locking, fuel filler flap
11	Central locking button
12	Trunk lock central locking system
13	Automatic soft-close drive in the trunk lock
14	Rear, driver's side central locking system
15	Rear, driver's side illuminated entry system
16	Hall sensors for lock barrel, door contact, driver's-door central locking system
17	Driver's-door illuminated entry system
18	Valet switch
19	Remote control receiver in diversity module
20	Exterior trunk button
K-CAN2	Bodyshell CAN2
KI. 30B	Terminal 30, basic operation
LIN-Bus	Local Interconnect Network bus
GPRL	Luggage compartment light

K-CAN signals at Car Access System 4

CAR ACCESS SYSTEM K-CAN SIGNALS CHART

In/out	Information	Source/sink	Function
In	Crash signal	Crash sensor > Advanced Crash Safety Management	Unlock central locking in the event of a crash
In	Driving speed	Wheel-speed sensor > Integrated Chassis Management	Lock central locking from a defined driving speed
Out	Hall sensor status, driver's-door lock barrel	Driver's-door lock barrel > Footwell module	Comfort opening of vehicle
Out	Hall sensor status, driver's-door lock barrel	Driver's-door lock barrel >	Comfort closing of vehicle Footwell module

The radio signal from the ID transmitter is received by the rear window antenna. The remote control receiver integrated in the diversity module (19) forwards the signal to the Car Access System (2). After the signal has been successfully checked, the Car Access System issues a request for control of the central locking system. The Car Access System is the master control unit for the central locking system.

The junction box electronics module (4) executes the unlocking or locking of the vehicle.

The footwell module (1) evaluates the status of all door contacts (6, 8, 14 and 16). It communicates the current status on the KCAN2. This means, for example, that the Car Access System is able to prevent locking when the driver's door is open.

The status of the center-lock button (3) is evaluated by the Car Access System and communicated over the K-CAN2. Depending on the status, the junction box electronics module activates central locking. The junction box electronics modules is also responsible for registering the status and activating central locking in the trunk.

The junction box electronics module is also responsible for controlling the fuel filler flap (10).

The footwell module evaluates the signals from the Hall sensors for the lock barrel (16) and makes this information available on the K-CAN2.

With this information, the Car Access System knows the status of the door lock in the driver's door. This is important if a request is issued to unlock or lock the vehicle using the ID transmitter, for example.

The central locking button is integrated in the underside of the trunk and is part of the Comfort Access option.