Rear lid unlocking and Soft Close Automatic

With rear lid unlocking, the rear lid lock is unlocked electrically when the rear lid is opened.

With Soft Close Automatic, the rear lid is closed under controlled conditions by a sensor-controlled electric drive.

Brief description of components

CAS Car Access System

The CAS Car Access System control unit contains the functions of

• radio remote control,
  
• the ignition starter switch,
  
• the terminal control and
  
• the vehicle immobilizer.
  

It is also the gateway module between the K-CAN SYSTEM and K-CAN PERIPHERALS data buses.

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

DM door module

The door modules register the signals of the switches and sensors installed in the doors and control the drives installed in the doors. Information is received and sent via the K-CAN PERIPHERALS data bus.

Power module

As well as other functions, the power module also contains the rear lid unlocking function and Soft Close Automatic for the rear lid.

Central locking drive, rear lid

The central locking drive is installed in the rear lid. It is activated by the power module and unlocks the mechanical rear lid lock. The central locking drive incorporates the rear lid contact, which signals to the power module 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.

Hotel switch

It is no longer possible to open or close the rear lid when the hotel switch is actuated.

Main functions

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:

• The rotary latch of the rear lid lock is closed,
  
• the rear lid contact is open (no ground signal),
  
• the Soft Close Automatic drive is at bottom dead centre,
  
• the position switch in the SCA drive is open (no ground signal).
  

Rear lid open

• The rotary latch of the rear lid lock is open,
  
• the rear lid contact is closed (connects to ground),
  
• the Soft Close Automatic drive is at top dead centre,
  
• the position switch in the SCA drive is closed (connects to ground).
  

Closing rear lid

The rear lid is closed by the SCA drive. 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 centre. The position switch in the SCA drive opens at bottom dead centre. The SCA drive stops.

Opening rear lid

The rear lid lock can be unlocked at the following operating locations:

• Rear lid button in rear lid
  
• Remote control
  

The rear lid lock is unlocked by the central locking drive. The Soft Close Automatic drive is activated when the power module detects via the rear lid contact that the lock is open. The drive is active until top dead centre is reached and the position switch in the drive connects to ground.

Deactivating SCA drive

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

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

Anti-repeat circuit

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