Part I

Automatic Luggage Compartment Lid ('Tailgate') Actuation

Automatic luggage compartment lid ('tailgate') actuation
In F07 for the first time a luggage compartment lid system with 2 tailgates, each to opened independently of the other, has been installed. Only ever one tailgate can be opened at any given time. This means that F07 delivers the benefits of a Saloon and of a Touring model.







Depending on requirements, either the small or the large tailgate can be opened. Each tailgate has its own, separate tailgate lock.

The loading conditions are as follows:







Small tailgate
The small tailgate can only be opened or closed manually.
The following operating elements can be used to unlock the small tailgate at vehicle standstill:
- Tailgate button, external, central (vehicle unlocked)
- Tailgate button in passenger compartment
- ID transmitter

The small tailgate can be unlocked when the vehicle is locked: this involves using the Comfort Access feature via the external, central tailgate button.
The small tailgate is closed manually against 2 gas pressure springs.







Large tailgate
On vehicles without automatic luggage compartment lid actuation, the large tailgate is equipped with 2 spring struts. On vehicles with automatic luggage compartment lid actuation, the large tailgate is equipped with 2 spindle drives.
The automatic luggage compartment lid actuation will be offered from series introduction as optional equipment.
The automatic luggage compartment lid actuation improves access comfort to the vehicle by enabling the large tailgate to be opened or closed at the touch of a button. A spindle-driven system is employed for opening and closing the large tailgate.
Manual opening or closing of the large tailgate is possible at any time with the tailgate open.
The following operating elements can be used to unlock the large tailgate electrically at vehicle standstill:
- Tailgate button, external, right (vehicle unlocked)
- ID transmitter

The large tailgate can be unlocked when the vehicle is locked: this involves using the Comfort Access feature via the external, right-hand tailgate button.
The Central Information Display (CID) enables the opening height of the large tailgate to be adjusted. The incompletely opened large tailgate can only be opened further using the internal tailgate button: "Open tailgate further". The maximum selectable opening height is about 2290 millimeter (highest contour on tailgate).

NOTE: Observe the opening height.

Ensure that, when opening the large tailgate fully, there is enough room to do so, otherwise the tailgate could get damaged.







The following operating elements can be used to close the large tailgate electrically at vehicle standstill:
- Tailgate button, external, right
- Inner tailgate button "Close tailgate" (only when large tailgate is open)
- Deadlocking with internal tailgate button (optional equipment, Comfort Access, and only when large tailgate is open)
- ID transmitter (press and hold down the button)

One function for the deadlocking system is central locking of the tailgate. The internal button for deadlocking of the tailgate forms part of the Comfort Access optional equipment. The internal button for deadlocking of the tailgate is only accessible when the small or large tailgate is open. By pressing the internal tailgate button for deadlocking, all doors are locked and centrally deadlocked. The status is evaluated by the Car Access System (CAS). Whenever the internal tailgate button for deadlocking is pressed, this status is detected by the Car Access System (CAS).
Locking and deadlocking are triggered. Prerequisite for deadlocking: front doors must be closed.
Whenever the internal tailgate deadlocking button is pressed while the large tailgate is open, the large tailgate is also opened by the automatic luggage compartment lid actuation function.
The following illustration shows the optional equipment for the automatic luggage compartment lid actuation.







Brief component description
The following components are described for the automatic luggage compartment lid actuation:
- Control unit, automatic luggage compartment lid actuation
- Central information display (CID)
- Controller (CON)
- Car Access System (CAS)
- Footwell module (FRM)
- Junction box electronics (JBE)
- Central gateway module (ZGM)
- Spindle drives
- ID transmitter
- External tailgate buttons
- Internal tailgate buttons
- Tailgate button in passenger compartment

Control unit, automatic luggage compartment lid actuation







The control unit for the automatic luggage compartment lid actuation (HKL) controls and monitors the functions of the automatic luggage compartment lid actuation. Using the K-CAN, the automatic luggage compartment lid actuation control unit (HKL) detects the status of the tailgate contact switch. This status is one of the triggering criteria for tailgate movement. The control unit on the automatic luggage compartment lid actuation (HKL) is connected to terminal 30g. For load current to the spindle drives, the control unit on the automatic luggage compartment lid actuation (HKL) is also connected to terminal 30. The automatic luggage compartment lid actuation needs a voltage range of between 9 V and 16 V. Outside this voltage range, these functions cannot be assured.
Two Hall sensors are installed on each spindle drive. These monitor tailgate movement. The control unit on the automatic luggage compartment lid actuation (HKL) also monitors the power consumption of the spindle drives. The rise in current when locking the large tailgate stops tailgate movement.
Whenever the large tailgate locks when closing, the automatic luggage compartment lid actuation reverses slightly to release this locking action. Locking action when opening the large tailgate stops tailgate movement. No reversing action takes place.

Central information display (CID)
The Central Information Display (CID) is the graphical display unit for the user interface of all convenience functions and some vehicle functions.
The Central Information Display (CID) is a bus user on the body CAN. The body CAN exchanges commands and information.







The controller (CON) is the central operating element for the Central Information Display (CID).
A menu in the Central Information Display (CID) enables the opening height of the large tailgate to be adjusted.

Controller (CON)
The controller (CON) is connected to the Central Information Display (CID) via the body CAN. The controller (CON) is the central control element for all vehicle functions that can be selected and configured on the Central Information Display (CID). The control panel and control unit of the controller (CON) have been combined to form one component.
There are 7 fixed selector buttons arranged around the controller. These selector buttons now enable selection of half of all the submenus.







A menu on the central information display (CID) enables the controller (CON) to adjust the opening height of the large tailgate. The automatic luggage compartment lid actuation opens the large tailgate, but only up to the predefined opening height (choose from 5 opening heights).







Car Access System (CAS)
The Car Access System (CAS) is installed beside the steering column. The Car Access System (CAS) is responsible for the central locking function. The Car Access System (CAS) therefore enables the tailgates to be unlocked. On vehicles with Comfort Access, the Car Access System (CAS) is also responsible for deadlocking. The Car Access System (CAS) receives the signal from the ID transmitter and checks it. After this check, the Car Access System (CAS) issues the following releases:
- release for unlocking the tailgate to the junction box electronics (JBE)
- release to operate the automatic luggage compartment lid actuation to the automatic luggage compartment lid actuation control unit (HKL).

The Car Access System (CAS) transmits the status of "terminal 50 on" via the K-CAN2. The control unit on the automatic luggage compartment lid actuation (HKL) prohibits activation of the spindle drives during engine starts, or interrupts movement in progress. This means more voltage is available for the starter motor.







Footwell module (FRM)
The footwell module (FRM) actuates the interior lighting of the vehicle.
Whenever the exterior lights are switched on, the footwell module (FRM) provides access to terminal 58g via Controller Area Network bus, local interconnect network bus, provided that direct wiring exists. The brightness level for function lighting is not dimmed and is activated at full intensity.
All footwell module (FRM) outputs for interior lighting are pulse-width modulated. This achieves a constant and uniform level of brightness for interior lighting despite fluctuations in the vehicle voltage. The footwell module (FRM) also provides power to the lighting for the tailgate button in the passenger compartment.







Junction box electronics (JBE)
The central locking system for the tailgate is activated by an output stage in the junction box electronics (JBE).
The junction box electronics (JBE) unlock or unlock the vehicle. The relays for locking and unlocking are located in the junction box electronics (JBE). The junction box electronics (JBE) are plugged into the front power distribution box.
The tailgate contact switches switch to earth whenever the tailgate is closed. The statuses of the tailgate contact switch are evaluated and made available by the junction box electronics (JBE). The junction box electronics (JBE) control the central locking system in the tailgate.
The statuses of the external tailgate buttons are read by the junction box electronics (JBE) and are then forwarded to the Car Access System (CAS).







Central gateway module (ZGM)
The Central Gateway Module (ZGM) links all data buses to one another. This enables the Gateway function on the Central Gateway Module (ZGM) to exchange data between the various different bus systems.







Spindle drives
On vehicles with automatic luggage compartment lid actuation, spindle drives are installed to left and right sides of the large tailgate instead of spring struts. The spindle drive consists of the following components:







The automatic luggage compartment lid actuation control unit (HKL) controls the spindle drive. The spindle drive enables the spindles to be rotated in both directions of rotation. The rotational movements of the spindles act on the spring pack via the transmission ratio:
- The transmission ratio applies load to the spring pack > opens the large tailgate through the driving power of the spindle drive
- The transmission ratio relieves load on the spring pack > closes the large tailgate using the spring force of the spring pack

The control unit on the automatic luggage compartment lid actuation (HKL) monitors the power consumption levels of the spindle drives. The rise in current when locking the large tailgate stops tailgate movement. There 2 Hall sensors integrated in each spindle drive. The Hall sensors and the power consumption monitoring function detect locking action.