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

GF80.20-P-0005FL Central Locking (CL [ZV]), Function

Central locking (CL [ZV]), general
The CL controls electric locking and unlocking of the vehicle doors, trunk lid (model 212.0) or the liftgate (model 212.2.) and the fuel filler flap.

The following controls are available:
- Transmitter key (A8/1)
- Remote trunk lid release button (S15/1) (model 212.0 without code (881) Remote trunk closing (RTC))
- Driver trunk lid control button (S15/3) (model 212.0 with code (881) Remote trunk closing (RTC))
- Driver liftgate control button (S15/3) (model 212.2)
- Left front door central locking interior switch (S85/5)
- Right front door central locking interior switch (S85/6)
- Trunk lid contact switch (S88/6) (model 212.0 with code (887) Valet Parking)
- Trunk lid emergency opening switch (S88/10) (model 212.0 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 of trunk lid (Model 212.0 without code (887) Valet Parking)
^ Function sequence for additional door lock (with code (885) Extended theft protection)
^ Function sequence for play protection

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

Additional function requirements for emergency opening in event of crash
^ Vehicle is locked

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 the corresponding message to front SAM control unit with fuse and relay module (N10/1) and electronic ignition lock control unit (N73) via the chassis CAN (CAN E).

The front SAM control unit transmits the message via the interior CAN (CAN B) to the following control units:
- Left front door control unit (N69/1)
- Left front door control unit (N69/1)
- Left rear door control unit (N69/3)
- Right rear door control unit (N69/4)

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.

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 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.

Additional function requirements for additional door lock
^ Interior protection activated (with code (882) Interior monitoring (only with ATA))
^ Function coded in front SAM control unit
^ All doors closed

Function sequence for additional door lock
When locking the CL [ZV], 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.
Upon locking with the central locking, the electronic ignition lock control unit also sends the command "Additional locking" to the following control units, via the interior CAN:
- Left front door control unit
- Right front door control unit
- Left rear door control unit
- Right rear door control unit

The following actuator motors are then actuated:
- Left front door additional door lock actuator motor (A85m4) by left front door control unit
- Right front door additional door lock actuator motor (A85/1m4) by right front door control unit
- Left rear door additional door lock actuator motor (A85/3m4) by left rear door control unit
- Right rear door additional door lock actuator motor (A85/4m4) by right rear door control unit

Function sequence for play protection
Each actuation of the CL [ZV] is counted by the electronic ignition switch control unit. The maximum number of actuations is 40. If this value is reached, additional actuation requests are not accomplished for the CL [ZV].
Every t = 7 s one actuation is deducted from the current meter reading.
Actuation of the CL [ZV] again is possible only after dropping below this value again.