GF80.20-P-0005CW Central Locking (CL), Function

GF80.20-P-0005CW Central Locking (CL), Function

General information
The central locking (CL) controls electric locking and unlocking of the vehicle doors, fuel filler flap and trunk lid (model 204.0) or tailgate (model 204.2).

The following controls are available:
- Transmitter key (A8/1)
- Trunk lid unlock button (S15/1) (on model 204.0)
- Left front door central locking interior switch (S85/5)
- Right front door central locking interior switch (S85/6)
- Trunk lid emergency opening switch (S88/10) (model 204.0 With code (494) USA version) (only opening trunk lid, the remaining CL remains locked)

The CL comprises the following partial functions:
^ Function sequence for emergency opening in event of crash
^ Function sequence for mechanical locking trunk lid (model 204.0 with code (494) USA version)
^ Function sequence for later closing trunk or tailgate
^ Function sequence for door auxiliary lock (on vehicles for Great Britain)
^ Function sequence for play protection

Further partial functions are described in separate documents:
^ Central locking operation with transmitter key, function
^ Locking/unlocking vehicle with inside switch, function
^ Automatic locking, function

Function sequence for emergency opening in event of crash
The emergency opening function unlocks the doors of the vehicle after an accident. The supplemental restraint system control unit (N2/10) transmits a corresponding message to the electronic ignition switch control unit (N73) with chassis CAN. After a waiting time of t = 8 to 11 s, the doors are unlocked.

The emergency opening function overrides all other central locking functions. When the vehicle has been locked from the outside, the emergency opening function is not active. In the event of rear end collision, the CL is unlocked without waiting time.

Function sequence for mechanical locking trunk lid
By turning the lock cylinder on the trunk lid with the emergency key, the trunk lid contact switch (S88/6) is actuated. This signal reads in the rear SAM control unit with fuse and relay module (N10/2) and inhibits opening requests from the other control points.

Function sequence for later closing trunk or tailgate
If the trunk lid or the tailgate is closed later, this is recognized by the trunk lid rotary tumbler switch (M14/7s1) (model 204.0) or tailgate rotary tumbler switch (M147/s1) (model 204.2). The status is transmitted by the rear SAM control unit with interior CAN. The electronic ignition switch control unit then checks, whether all doors are closed. If this is the case, the trunk lid or tailgate is locked, which is indicated by a visual feedback signal.

Function requirements for additional door lock
^ Interior protection activated (with code (882) Interior monitoring (only with ATA))
^ Function in front SAM control unit with fuse and relay module (N10/1) coded

Function sequence for additional door lock
When locking the CL, the mechanical interior actuation feature is switched off, so that the doors can no longer be opened from the inside. This prevents breaking in into the vehicle by smashing in a window and opening a door from inside
When the CL is locked, the electronic ignition switch control unit additionally transmits the command "Additional locking" to the left front door control unit (N69/1), right front door control unit (N69/2), left rear door control unit (N69/3) and right rear door control unit (N69/4) with the interior CAN.

The corresponding door control unit actuates the corresponding additional door lock actuator motor (A85m4, A85/1m4, A85/3m4 and A85/4m4) when locking.

Function sequence for play protection
Each actuation of the CL is counted by the electronic ignition switch control unit. Every t = 7 s one actuation is deducted from the current meter reading. The maximum number of actuations is 40.
After reaching this value, further actuation requests for the CL are not performed. $ Only if the value is not reached, it is possible to reactuate the CL.