Central Locking (CL (ZV)), Function - GF80.20-S-0005TRB

Model 447.6/7 

except code XM0 (Facelift) 

Model 448.7 

Courtesy of MERCEDES-BENZ USA

Central locking (CL [ZV]), general 

The CL electrically locks and unlocks the vehicle doors, the liftgate and the rear-end doors.

The CL can be operated with the following control elements:

• Transmitter key
• Driver central locking interior operation switch
• Left seat climate switch group with CODE H16 (Seat heater for driver) or with CODE SF1 (Electrically adjustable driver seat)

Additional function requirements for operation with transmitter key 

• Circuit 15COFF"

Function sequence for control with transmitter key 

The transmitter key operation comprises the following partial functions:

The CL comprises the following partial functions:

• Function sequence for control with transmitter key 
• Function sequence for locking or unlocking CL 
• Function sequence for locking CL automatically 
• Function sequence for emergency opening in event of crash 
• Function sequence for play protection 
• Function sequence for preset "Selective" or "Global" unlocking 
• Function sequence for locking or unlocking 
• Function sequence for locking feedback 

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

If the unlock button and the lock button on the transmitter key are pressed simultaneously for t = 5 s, the unlocking mode is changed from "global" to "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 liftgate are unlocked.

Selectively unlocking:

On model 447.6: 

When the unlock button the transmitter key is pressed once, the driver door and the passenger door are unlocked.

On model 447.7, 448.7: 

When the unlock button the transmitter key is pressed once, only the driver door is opened. When the unlock button on the transmitter key is pressed again, all vehicle doors as well as the liftgate are unlocked.

Function sequence for locking or unlocking 

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, AM and CL antenna amplifier.

The electronic ignition switch control unit (EZS) checks the access authorization of the transmitter key. If the access authorization is valid, the electronic ignition lock control unit (EZS) transmits the "Lock" or "Unlock" request over the interior CAN to the following control units:

• Left front door control unit
• Right front door control unit
• Signal acquisition and actuation module (SAM) control unit
• Left sliding door control unit (E-LSTL) with CODE T56 (Electrical actuation for left sliding door)
• Right sliding door control unit (E-LSTR) with CODE T55 (Electrical actuation for right sliding door)
• Left front door control unit: 

  The left front door control unit locks or unlocks the left driver door via the left front door central locking actuator.

• Right front door control unit: 

  The right front door control unit locks or unlocks the right passenger door via the right front door central locking actuator.

  • Signal acquisition and actuation module (SAM) control unit: 

    The signal acquisition and actuation control unit (SAM) locks or unlocks:

    • The mechanical left sliding door via the mechanical left sliding door central locking actuator (with CODE T19 (Left sliding door)).
    • The right mechanical sliding door via the right mechanical sliding door central locking actuator.
    • The liftgate via the opening assist.
    • The rear-end door via the rear-end door actuation central locking actuator (with CODE W50 (Two-wing rear-end door, 180 degrees without window) or with CODE W54 (Two-wing rear-end doors, opening to sidewall).
    • Left sliding door control unit (E-LSTL) with CODE T56 (Electrical actuation for left sliding door): 

      The left sliding door control unit (E-LSTL) locks or unlocks the left electrical sliding doors via the electrical left sliding door central locking actuator.

    • Right sliding door control unit (E-LSTR) with CODE T55 (Electrical actuation for right sliding door): 

      The right sliding door control unit (E-LSTR) locks or unlocks the right electric sliding door via the right electric sliding door central locking actuator.

Vehicles with CODE FY1 (Theft protection package) or with CODE FZ5 Anti-theft alarm system: If the driver door in the locked vehicle is opened manually with the emergency key, the anti-theft alarm system (ATA [EDW]) triggers an alarm.

Function sequence for locking feedback 

For closing feedback the status of the vehicle doors, liftgate and rear-end doors (open or closed) is sensed over the following switches:

• Left front door rotary tumbler microswitch
• Right front door rotary tumbler microswitch
• Left sliding door rotary tumbler microswitch (with CODE T56 (Electrical actuation for left sliding door))
• Right sliding door rotary tumbler microswitch (with CODE T55 (Electrical actuation for right sliding door))
• Left mechanical sliding door rotary tumbler microswitch (with CODE T19 (Left sliding door))
• Right manual sliding door rotary tumbler microswitch
• Liftgate rotary tumbler microswitch
• Right rear-end door rotary tumbler switch (with CODE W50 (Two-wing rear-end door, 180 degrees without window) or with CODE W54 (Two-wing rear-end doors, opening to sidewall))
• Left rear-end door rotary tumbler switch (with CODE W50 (Two-wing rear-end door, 180 degrees without window) or with CODE W54 (Two-wing rear-end doors, opening to sidewall))
• Left front door control unit: 

  The left front door control unit reads in the status of the left front rotary tumbler microswitch directly and sends it via interior CAN to the electronic ignition lock control unit.

• Right front door control unit: 

  The right front door control unit reads in the status of the right front rotary tumbler microswitch directly and sends it via interior CAN to the electronic ignition lock control unit.

• Signal acquisition and actuation module (SAM) control unit: 

  The signal acquisition and actuation module (SAM) control unit directly reads in the status of the following components:

  • Left mechanical sliding door rotary tumbler microswitch (with CODE T19 (Left sliding door))
  • Right manual sliding door rotary tumbler microswitch
  • Liftgate rotary tumbler microswitch
  • Right rear-end door rotary tumbler switch (with CODE W50 (Two-wing rear-end door, 180 degrees without window) or with CODE W54 (Two-wing rear-end doors, opening to sidewall))
  • Left rear-end door rotary tumbler switch (with CODE W50 (Two-wing rear-end door, 180 degrees without window) or with CODE W54 (Two-wing rear-end doors, opening to sidewall))

The signal acquisition and actuation module (SAM) control unit transmits the status to the electronic ignition lock control unit (EZS) via the interior CAN.

• Left sliding door control unit (E-LSTL) (with CODE T56 (Electrical actuation for left sliding door)): 

  The left front door control unit (E-STL) reads in the status of the left front rotary tumbler microswitch directly and sends it via interior CAN to the electronic ignition lock control unit (EZS).

• Right sliding door control unit (E-LSTR) (with CODE T55 (Electrical actuation for right sliding door)): 

  The right sliding door control unit (E-STL) reads in the status of the right front rotary tumbler microswitch directly and sends it via interior CAN to the electronic ignition lock control unit (EZS).

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

Visual locking feedback: 

Visual locking feedback is output over the turn signals.

The electronic ignition lock control unit (EZS) transmits the request "Lock" or "Unlock" via the interior CAN to the signal acquisition and actuation module control unit (SAM). The signal acquisition and actuation module control unit (SAM) 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 liftgate or the rear-end is still open when locking, there is no visual feedback.

Detailed information for sensing the status of the vehicle doors, liftgate or rear-end doors is given in the chapter "locking or unlocking".

Detailed information on performing the hazard warning flasher function is included in the function description "Exterior lights, function" in the partial function "Turn signal light actuation, function".

Additional function requirements for locking/unlocking CL inside switch 

• Vehicle must not be locked from outside with transmitter key.

Function sequence for locking or unlocking CL 

The CL can be operated via the driver central locking inside door handle switch or left seat climate control switch group (with CODE H16 (Seat heater for driver) or with CODE SF1 (Electrically adjustable driver seat)).

The central locking open button and central locking close button are integrated into the driver central locking inside door handle switch. If one of the two buttons is pressed, all vehicles doors as well as the liftgate are locked or unlocked.

On vehicles with CODE H16 (Seat heater for driver) or with CODE SF1 (Electrically adjustable driver seat):

The central locking open button and central locking close button are integrated into the left seat climate control switch group. If one of the two buttons is pressed, all vehicles doors as well as the liftgate are locked or unlocked.

The left front door control unit directly reads in the status of the driver central locking inside door handle switch or the status of the left seat climate control switch group (with CODE H16 (Seat heater for driver) or with CODE SF1 (Electrically adjustable driver seat)) and transmits it to the electronic ignition lock control unit (EZS) via the interior CAN. The electronic ignition lock control unit transmits the request "Lock" or "Unlock" via the interior CAN to the following control units:

• Signal acquisition and actuation module (SAM) control unit
• Left front door control unit
• Right front door control unit
• Left sliding door control unit (E-LSTL) (with CODE T56 (Electrical actuation for left sliding door))
• Right sliding door control unit (E-LSTR) (with CODE T55 (Electrical actuation for right sliding door))

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

The CL can only be locked, when all doors are closed.

Opening a door from the inside when the CL is locked:

Every door can always be opened from the inside. At least the corresponding door is opened mechanically.

Additional function requirements for automatically locking CL 

• CL [ZV] unlocked
• Function activated via driver central locking inside door handle switch or left seat climate control switch group (with CODE H16 (Seat heater for driver) or with CODE SF1 (Electrically adjustable driver seat))

Function sequence for locking CL automatically 

The CL function comprises the following partial functions:

• Function sequence for locking CL depending on vehicle speed 
• Function sequence for automatic relocking 

Function sequence for locking CL depending on vehicle speed 

The function is activated by pressing the central locking close button for more than 5 seconds. The function is deactivated by pressing the central locking open button for more than 5 seconds. An acknowledgment tone is output via the instrument cluster speaker in the driver footwell. The left front door control unit reads in the status of the central locking button and transmits it via the interior CAN to the electronic ignition lock control unit (EZS). Then the electronic ignition lock control unit (EZS) transmits the function status to the instrument cluster (IC) via the interior CAN. The instrument cluster (IC) control unit directly actuates the instrument cluster speaker in the driver footwell.

On vehicles with CODE H16 (Seat heater for driver) or with CODE SF1 (Electrically adjustable driver seat):

The central locking open button and central locking close button are integrated into the left seat climate control switch group. The function is activated by pressing the central locking close button for more than 5 seconds. The function is deactivated by pressing the central locking open button for more than 5 seconds. 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 both central locking buttons via the left front door LIN and transmits it via the interior CAN to the electronic ignition lock control unit (EZS). Then the electronic ignition lock control unit (EZS) transmits the function status to the instrument cluster (IC) via the interior CAN. The instrument cluster (IC) control unit directly actuates the instrument cluster speaker in the driver footwell.

The CL acts as follows depending on the vehicle speed:

• Vehicle speed above 3 km/h:

The liftgate/rear-end door can no longer be opened from outside.

• Vehicle speed above 15 km/h:

All vehicles doors, liftgate or rear-end doors are locked.

The Electronic Stability Program (ESP) control unit sends the vehicle speed via chassis CAN to the electronic ignition lock control unit (EZS). The electronic ignition lock control unit (EZS) evaluates this information and sends the "Locking" request to the following control units via interior CAN:

• Signal acquisition and actuation module (SAM) control unit
• Left front door control unit
• Right front door control unit
• Right sliding door control unit (E-LSTR) (with CODE T55 (Electrical actuation for right sliding door))
• Left sliding door control unit (E-LSTL) (with CODE T56 (Electrical actuation for left sliding door))

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

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

On vehicles with CODE H16 (Seat heater for driver) or with CODE SF1 (Electrically adjustable driver seat) the CL is unlocked via the central locking open button in the left seat climate control switch group.

If the CL is unlocked, it also remains unlocked at vehicle speeds above the corresponding limits. 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 

• CL unlocked with transmitter key

Function sequence for automatic relocking 

After the CL is 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 liftgate or a rear-end door has been opened previously. Visual or acoustic locking feedback is not output.

FY1 FZ5With the relocking feature, the antitheft alarm system (ATA) (on vehicles with CODE () Theft protection package or with CODE () Anti-theft alarm system) is also activated.

Additional function requirement for emergency opening in event of crash 

• Vehicle is locked (not via transmitter key)

Function sequence for emergency opening in event of crash 

The emergency opening function unlocks the doors of the vehicle in the event of a crash. The Supplemental Restraint System (SRS) control unit transmits the crash signal via chassis CAN to the electronic ignition lock control unit (EZS). The electronic ignition lock control unit (EZS) sends the signal "Emergency opening central locking" via the interior CAN to the following control units:

• Left front door control unit
• Right front door control unit
• Right sliding door control unit (E-LSTR) (with CODE T55 (Electrical actuation for right sliding door))
• Left sliding door control unit (E-LSTL) (with CODE T56 (Electrical actuation for left sliding door))
• Signal acquisition and actuation module (SAM) control unit

After a waiting time of 8 to 11 s, the doors, the liftgate and the rear-end doors are unlocked.

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 play protection 

Each actuation of the CL [ZV] is counted by the electronic ignition switch control unit (EZS). The maximum number of actuations is 45. If this value is reached, additional actuation requests are not accomplished for the CL [ZV]. The current counter status is reduced by one actuation every 7 seconds. Actuation of the CL again is possible only after dropping below the value of 45 again.

	Electrical function diagram for central locking (CL [ZV])	Model 448.7	PE80.20-S-2050-97VDB
		Model 447.6/7 except code XM0 (Facelift)	PE80.20-S-2050-97TRB
	Overview of system components for theft protection and locking		GF80.00-S-9999TRA