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

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Model 205, 253 

G14187690Courtesy of MERCEDES-BENZ USA

Shown on Model 205 and Model 253 

Central locking (CL [ZV]), general 

The CL electrically locks and unlocks the vehicle doors, the trunk lid or liftgate and the tank cap.

The CL can be operated with the following control elements:

On Model 205.012/047/147/212/247 and Model 253.354/954 vehicles, the fuel tank has to be vented via the refueling intention detection switch in the driver door before refueling. The status of the refueling intention detection switch is read in directly by the left front door Control unit.

The CL comprises the following partial functions:

Additional function requirements for operation of CL with transmitter key 

Function sequence for operating CL with transmitter key 

The transmitter key operation comprises the following partial functions:

Function sequence for preset "Selective" or "Global" unlocking 

If the unlock and lock buttons on the transmitter key are pressed simultaneously for t = 5 s, the unlocking mode toggles between "global" and "selective". The indicator lamp illuminates in the transmitter key.

Globally unlocking:

When the unlock button on the transmitter key is pressed, all vehicle doors as well as the trunk lid or liftgate are unlocked. Opening the trunk lid is permitted.

Selectively unlocking:

When the lock button the transmitter key is pressed once, only the driver door is unlocked and the tank cap is opened. When the unlock button on the transmitter key is pressed again, all vehicle doors as well as the trunk lid or liftgate are unlocked.

Function sequence for locking or unlocking CL 

Vehicles without code (889) KEYLESS-GO and except code 893 (KEYLESS-GO start function):

When the unlock button or lock button on the transmitter key is actuated, it sends a radio signal to the electronic ignition lock Control unit via the rear window antenna and the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier.

Vehicles with code (889) KEYLESS-GO or code (893) KEYLESS-GO start function:

When the unlock or lock button on the transmitter key is actuated, it sends a radio signal to the KEYLESS-GO Control unit via the rear window antenna and the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier. The KEYLESS-Go Control unit sends this radio signal to the electronic ignition lock Control unit via interior CAN. The electronic ignition switch Control unit checks the access authorization of the transmitter key. If the access authorization is valid, the electronic ignition switch Control unit transmits the "Lock" request via the interior CAN to the following Control units:

The left front door Control unit locks or unlocks the left front door lock via the left front door central locking motor.

The right front door Control unit locks or unlocks the right front door lock via the right front door central locking motor.

Model 205.0/1/2, 253:

The left rear door Control unit locks or unlocks the left rear door lock via the left rear door central locking motor.

The right rear door Control unit locks or unlocks the right rear door lock via the right rear door central locking motor.

Model 205.4:

The rear SAM Control unit locks or unlocks the stowage compartment in the center console via the stowage compartment central locking actuator motor.

Opening the trunk lid or liftgate via trunk lid/liftgate external operation switch is enabled or disabled by the rear SAM Control unit.

The status of the trunk lid/liftgate external operation switch is directly read in by the rear SAM Control unit.

The rear SAM Control unit disables the opening request from the tank cap central locking actuator or enables it. If the tank cap is pressed (opening request), a signal is sent to the rear SAM Control unit by the tank cap central locking actuator. The rear SAM Control unit checks whether the opening request is permissible. If so, the rear SAM Control unit actuates the electric motor in the tank cap central locking actuator and the locking hooks are released.

IMPORTANT Model 205.012/047/147/212/247, 253.354/954

In the case of hybrid vehicles, the socket for the charging cable is also locked or unlocked through the CL to prevent a charging cable from being disconnected or plugged in.

For the feedback signal, the status of the vehicle doors as well as the trunk lid or liftgate (open or closed) is detected via the following switches:

The left front door Control unit reads in the status of the left front door rotary tumbler switch directly and transmits it to the electronic ignition lock Control unit over the interior CAN.

The right front door Control unit reads in the status of the right front door rotary tumbler switch directly and transmits it to the electronic ignition lock Control unit over the interior CAN.

Model 205.0/1/2, 253:

The left rear door Control unit directly reads in the status of the left rear door rotary tumbler switch directly and transmits it to the electronic ignition lock Control unit over the interior CAN.

The right rear door Control unit directly reads in the status of the right rear door rotary tumbler switch directly and transmits it to the electronic ignition lock Control unit over the interior CAN.

The rear SAM Control unit directly reads in the status of the trunk lid/liftgate lock main catch switch and transmits it to the electronic ignition lock Control unit via the interior CAN.

IMPORTANT On vehicles with additional door lock, additional actuator motors are actuated. Detailed information is given in chapter "Additional door lock".

IMPORTANT If the driver door in the locked vehicle is opened mechanically with the emergency key, the anti-theft alarm system (ATA) triggers an alarm.

Function sequence feedback signal 

The user is given a visual and acoustic feedback signal when the CL is successfully locked or unlocked.

Acoustic feedback signal:

The acoustic feedback signal function is selected via the control level in the head unit. The selection is made via the Audio/COMAND control panel (without code 446 (Touchpad only)) or the touchpad (for code 446 (Touchpad only)) and is shown in the Audio/COMAND display. The Audio/COMAND control panel (without code 446 (Touchpad only)) or the touchpad (for code 446 (Touchpad only)) transmits the adjustment request via the telematics CAN to the head unit. The head unit generates the corresponding image data and sends a switch-on request to the Audio/COMAND display via telematics CAN. The image data is sent via the LVDS line to the Audio/COMAND display.

The head unit transmits the status of the acoustic feedback signal function via the user interface CAN, electronic ignition lock Control unit, and interior CAN to the front SAM Control unit.

When the acoustic feedback signal function is activated, the front SAM Control unit momentarily actuates the left horn and the right horn via the horn relay after successful unlocking or locking. For this purpose the electronic ignition lock Control unit transmits the "Lock" or "Unlock" request to the front SAM Control unit via the interior CAN.

The horns are actuated once during unlocking.

The horns actuated three times during locking.

If a door, the trunk lid, or the liftgate is still open while locking, no acoustic feedback signal is output.

IMPORTANT Detailed information for sensing the status of the vehicle doors as well as the trunk lid or liftgate is given in the chapter "Locking or unlocking CL".

Visual feedback signal:

The visual feedback signal is output via the turn signal indicator. The electronic ignition lock Control unit transmits the request "Lock" or "Unlock" to the front SAM Control unit via the interior CAN. The front SAM Control unit then activates the hazard warning flasher function. All turn signals are actuated synchronously on the vehicle.

The turn signals are actuated three times when unlocking.

The turn signals are actuated three times when locking.

If a door, the trunk lid, or the liftgate is still open while locking, no visual feedback signal is output.

IMPORTANT Detailed information for sensing the status of the vehicle doors as well as the trunk lid or liftgate is given in the chapter "Locking or unlocking CL".

Function sequence for trunk lid remote opening (Model 205.0/1/3 except CODE 881 (Remote trunk closing)) 

Vehicles except CODE 889 (KEYLESS-GO):

When the open trunk lid button on the transmitter key is pressed, it sends a radio signal to the electronic ignition key Control unit via the rear window antenna and the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier.

Vehicles with code 889 (KEYLESS-GO):

When the open trunk lid button on the transmitter key is pressed, it sends a radio signal to the KEYLESS-GO Control unit via the rear window antenna and the FM 1, AM, CL [ZV] and KEYLESS-GO antenna amplifier. The KEYLESS-GO Control unit sends this signal to the electronic ignition lock Control unit via interior CAN.

The electronic ignition switch Control unit checks the access authorization of the transmitter key. If the access authorization is valid, the electronic ignition switch Control unit sends request "Open trunk lid" to the rear SAM Control unit via interior CAN. The rear SAM Control unit then actuates the trunk lid/liftgate lock motor in the trunk lid/liftgate lock to unlock the trunk lid. The trunk lid is then opened mechanically by spring force as far as the upper stop.

Additional function requirements for vehicles with locking/unlocking inside switch 

Function sequence for locking/unlocking vehicle with inside switch 

The CL [ZV] can be operated with the left front door central locking inside door handle switch and right front door central locking inside door handle switch (except in ECE).

The vehicle function locking/unlocking with interior switch comprises the following partial functions:

Function sequence for locking/unlocking CL 

When the left front door central locking inside door handle switch or right front door central locking inside door handle switch is pressed (except in ECE), all vehicle doors, the trunk lid or the trunk lid or the liftgate are unlocked. Opening the trunk lid is permitted. The left front door Control unit directly reads in the status of the left front door central locking inside door handle switch and transmits it to the electronic ignition lock Control unit via the interior CAN. The right front door Control unit reads in the status of the right front door central locking inside door handle switch directly and transmits it to the electronic ignition lock Control unit over the interior CAN. The electronic ignition lock Control unit transmits the request "Lock" or "Unlock" via the interior CAN to the following Control units:

IMPORTANT Detailed information for actuation of individual CL components, is given in the chapter "Locking or unlocking CL".

When locking with the central locking interior actuation switch, the tank cap remains always unlocked.

When the driver door is open, all doors except the driver door, the trunk lid or the liftgate are locked.

When the passenger door is open, the locking operation of the CL is inhibited by the left front door central locking inside door handle switch. Opening a door from the inside when the CL is locked:

Basically each door can be opened from the inside (except with CODE 885 (Extended theft protection) or when the mechanical child safety lock on the rear doors (Model 205.0/1/2, 253 except CODE 494 (USA version)) is set to active). At least the corresponding door is opened mechanically.

If the vehicle is unlocked globally before locking, all vehicle doors as well as the trunk lid or liftgate are unlocked. Opening the trunk lid is permitted.

Additional function requirements for unlocking trunk lid (open) (Model 205.0/1/3/4 except CODE 881 (Remote trunk closing)) 

The instrument cluster sends the vehicle speed via user interface CAN to the electronic ignition lock Control unit.

Function sequence for unlocking trunk lid (opening) (Model 205.0/1/3/4 except CODE 881 (Remote trunk closing)) 

It is also possible to unlock or open the trunk lid with the driver trunk lid control button. The actuation of the trunk lid release button for t≥ 0.5 s is read in directly by the left front door Control unit and relayed via the interior CAN to the rear SAM Control unit. It then unlocks the trunk lid via the trunk lid/liftgate lock motor. The trunk lid is opened up to the upper stop by spring force.

Function sequence for opening through trunk lid emergency opening switch (Model 205.0/3/4 with code 494 (USA version)) 

On Model with code (494) USA version, opening the trunk lid via the trunk lid emergency opening switch is possible up to a defined speed regardless of the status of the CL. A person trapped in the trunk can open the trunk lid from inside. The trunk lid emergency switch is illuminated and is located on the inside of the trunk.

IMPORTANT The rear SAM Control unit actuates the symbol lighting in the trunk lid emergency opening function switch at a frequency of f = 1 Hz. The symbol lighting is actuated for t = 30 min when the trunk lid is open and for t = 60 min when the trunk lid is closed.

The rear SAM Control unit directly reads in the status of the trunk lid emergency opening switch. When the trunk lid emergency opening switch is pressed, the rear SAM Control unit actuates the trunk lid/liftgate lock motor to unlock the truck lid. The trunk lid is opened up to the upper stop by spring force.

Additional function requirements for automatically locking CL 

Function sequence for locking CL automatically 

The CL function comprises the following partial functions:

Function sequence for locking CL depending on vehicle speed 

The function is activated by pressing the central locking system close switch for t > 5 s and deactivated by pressing the central locking system open switch for t > 5 s. An acknowledgment tone is output via the instrument cluster speaker in the driver footwell. The left front door Control unit directly reads in the status of the central locking switch (S85/5s1 or S85/5s2) and transmits it to the electronic ignition lock Control unit via the interior CAN. The right front door Control unit directly reads in the status of the central locking switch (S85/6s1 or. S85/6s2) and transmits it to the electronic ignition lock Control unit via the interior CAN. Then the electronic ignition lock Control unit transmits the function status to the instrument cluster via the user interface CAN. The instrument cluster directly actuates the instrument cluster speaker in the driver footwell.

The CL acts as follows depending on the vehicle speed:

The trunk lid or liftgate can no longer be opened from outside.

All vehicle door and trunk lid or liftgate are locked.

The instrument cluster sends the vehicle speed via user interface CAN to the electronic ignition lock Control unit. The electronic ignition lock Control unit evaluates this information and sends the "Locking" request to the following Control units via interior CAN:

IMPORTANT Detailed information for actuation of individual CL components, is given in the chapter "Locking or unlocking CL".

The CL can be unlocked by opening a door from the inside or via the central locking inside door handle switch.

When the vehicle is unlocked by actuating the inside door handle central locking system switch, it remains unlocked even at vehicle speeds above the corresponding limit value. The vehicle is returned to the initial state when one of the doors is opened or c. 15 is switched on and off again.

If a door is opened while driving and then closed again and the vehicle speed is above the limit value for automatic locking, the door is locked again after it is closed.

additional function requirements for automatic relocking 

Function sequence for automatic relocking 

After the CL has been unlocked with the transmitter key, a waiting time of t = 40 s starts. After expiration of this waiting time, the CL is relocked if a door, the trunk lid or the liftgate has been opened previously. No visual or acoustic feedback signal is output.

The electronic ignition lock Control unit transmits the request "Lock" via the interior CAN to the following Control units:

IMPORTANT Detailed information for actuation of individual CL components, is given in the chapter "Locking or unlocking CL".

IMPORTANT Model 205, 253 with code 551 (Standard anti-theft alarm system (ATA))

The relocking also activates the anti-theft alarm system (ATA).

Additional function requirement for emergency opening in event of crash 

Function sequence for emergency opening in event of crash 

In case of a crash, the emergency opening function unlocks all doors and the liftgate. The supplemental restraint system Control unit sends the crash signal via user interface CAN to the electronic ignition lock Control unit and redundantly via a direct line to the front SAM Control unit.

The front SAM Control unit then generates a signal "Emergency opening" and transmits this signal via the interior CAN to the following Control units:

The doors, trunk lid or liftgate, and fuel filler cap are unlocked after a waiting time of t = 8 to 11 s. The exception here is a rear crash, when the doors, trunk lid, or the liftgate and tank cap are unlocked immediately.

IMPORTANT Detailed information for actuation of individual CL components, is given in the chapter "Locking or unlocking CL".

IMPORTANT The emergency opening function in event of a crash has priority over all other CL functions. When the vehicle has been locked from the outside, the emergency opening function is not active.

Function sequence for mechanical locking of trunk lid (Model 205.0/1/3/4 with CODE 887 (Separate trunk lid lock)) 

Actuating the switch for separate trunk lid locking means that the opening requests for the trunk lid are ignored. The status of the switch for separate trunk lid locking is read in directly by the front SAM Control unit and relayed to the rear SAM Control unit via interior CAN. The rear SAM Control unit then blocks the opening requests from the other controls.

Additional function requirements for additional door lock (with code (885) Extended theft protection) 

IMPORTANT Detailed information for sensing the status of the vehicle doors as well as the trunk lid or liftgate is given in the chapter "Locking or unlocking CL".

Function sequence for additional door lock (with code 885 (Increased theft protection)) 

When locking the CL, the connection between the inside door handle and door lock is switched off mechanically, so that the doors can no longer be opened from the inside. This is intended to prevent a door from being opened from the inside after breaking a window.

Upon locking with the CL, the electronic ignition lock Control unit also transmits the "Additional door locking" request via the interior CAN to the following Control units:

The left front door Control unit actuates the left front door additional door lock actuator motor.

The right front door Control unit actuates the right front door additional door lock actuator motor.

Model 205.0/1/2, 253:

The left rear door Control unit directly actuates the left rear door additional door lock actuator motor.

The right rear door Control unit directly actuates the right rear door additional door lock actuator motor.

Function sequence for play protection 

Each actuation of the CL [ZV] is counted by the electronic ignition lock Control unit. The maximum number of actuations is 40. If this value is reached, additional actuation requests are not accomplished for the CL [ZV]. One actuation is deducted from the current counter status every t = 7 s. Actuation of the CL again is possible only after dropping below the value of 40 again.

Function sequence for remote vehicle unlocking and/or vehicle remote locking (with code 348 (Emergency call/assist system) or with code 05U (Remote Online) or with code 360 (HERMES UMTS) and code 11U (Remote Online) or with code 362 (HERMES LTE)) 

The CL can be unlocked with the remote door unlock function e.g. in the case that a transmitter key is locked in the vehicle and a second transmitter key is not present. The CL can be locked with the remote door lock in the case that CL locking has been forgotten. The emergency call system Control unit (with code 348 (Emergency call/assist system)), the telematics services communication module (with code 05U (Remote Online)) or the HERMES Control unit (with code 360 (HERMES UMTS) and code 11U (Remote Online) or with code 362 (HERMES LTE)) transmits the corresponding request via diagnostics CAN to the electronic ignition lock Control unit.

Both services first require legitimation of the vehicle owner by the service center.

  Electrical function diagram for central locking (CL [ZV])   PE80.20-P-2050-97FBA 
  Overview of system components for theft protection and locking   GF80.00-P-9999RF 
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