Rear lid unlocking and Soft Close Automatic (SCA)

To open the trunk lid/tailgate, the trunk lid / tailgate lock is electrically unlocked by the trunk-lid / tailgate unlocking.

The trunk lid/tailgate is opened and closed with the trunk lid/tailgate lift (HKL).

With Soft Close Automatic (SCA), the trunk lid/tailgate is drawn in a controlled manner into the lock by a sensor-controlled electrical drive unit on closing.

Brief description of components

Car Access System (CAS)

The CAS Car Access System control module contains the functions of

The CAS Car Access System control module is also the gateway module between the data buses K-CAN SYSTEM and K-CAN PERIPHERALS.

The CAS controls all the higher-order functions of the central locking system.

Power module (PM)

As well as other functions, the power module (PM) also contains the trunk lid/tailgate unlocking function and Soft Close Automatic (SCA) for the trunk lid/tailgate.

Release drive for trunk lid/tailgate

The release drive is installed in the trunk lid/tailgate. It is activated by the power module (PM) and unlocks the mechanical trunk lid / tailgate lock. The release drive incorporates the rear lid contact, which signals to the power module (PM) the position of the rear lid lock.

SCA drive, rear lid

The SCA drive is installed in the body. The SCA drive incorporates a position switch, which records the position of the SCA drive. The SCA drive is controlled by the power module (PM).

Hotel switch

After operation of the hotel switch, the hotel setting is engaged. In the hotel setting, the button for opening the trunk lid/tailgate is deactivated on the remote control. The BOOT (S8) button on the front interior light unit on the headlining is also deactivated. The trunk lid/tailgate also remains locked when the vehicle is unlocked. The hotel switch is fitted in the upper glove box beneath the switch for setting the clock.

Main functions

Unlocking and opening the trunk lid/tailgate

To open the trunk lid/tailgate, the trunk lid / tailgate lock can be unlocked using the following controls:

The rear lid lock is unlocked by the release drive. If the power module (PM) is informed by the trunk-lid contact that the lock is open, the drive for the Soft Close Automatic (SCA) is activated to wards 'open' (top dead center). The drive is active until top dead center is reached and the position switch in the drive connects to ground.

Trunk lid/tailgate lift

See functional description: Trunk lid/tailgate lift

SCA functions and positions

The closing operation for the rear lid is performed by way of defined positions.

Defined positions

The defined positions for closing are:

Rear lid closed:

Rear lid open

Closing and locking the trunk lid/tailgate

To close the trunk lid/tailgate, the following controls can be used:

The rear lid is closed by the trunk lid/tailgate lift. As of ”pre-engage”, the drive for Automatic Soft Close draws the trunk lid/tailgate into the lock and runs until the lock is in the state ”locked”. The SCA drive is activated when the rear lid is pressed closed. In this case, the rear lid lock is pressed against the cam of the SCA drive and rotated. The rear lid contact is opened. The SCA drive is activated and moves towards bottom dead center. The position switch in the SCA drive opens at bottom dead center. The SCA drive stops.

Deactivating SCA drive

The SCA drive is deactivated after 5 seconds if the power module (PM) fails to detect arrival at top or bottom dead center. A fault is stored in the fault memory.

The functional sequence starts again when a signal change is signaled by the rear lid contact.

Anti-repeat circuit

An anti-repeat circuit prevents electronic components in the control module from overheating. The anti-repeat circuit permits a maximum of 15 activations in succession.