Fully Automatic Soft Top

Fully Automatic Soft Top

Fully automatic soft top
Opening and closing the electro-hydraulic soft top are fully automatic. Opening and/or closing the Soft Top takes around 22 seconds. Also when the vehicle is moving a low speeds if necessary (up to 40 km/h). During this, the soft top is moved via hydraulic cylinder. An electric motor unlocks and locks the soft top at the cowl panel.
After opening, the soft top is placed in the soft top compartment. Subsequently, the soft top compartment lid is closed automatically.
The soft top is operated via a rocker switch in the centre console. The soft top can also be operated via the lock barrel in the driver's door using the integrated key in the remote key.
If the "Comfort Access" (SA322) optional equipment is installed in the vehicle, the soft top can be opened and closed using the ID transmitter. The soft top can also be closed via the outside door handle electronics. The outside door handle electronics act as an operator interface for Comfort Access. The request to lock the soft top is activated by pressing an outer door handle. The request is only processed if the driver's door is closed. The door from which the request is being made must also be closed.

NOTICE: Convenient closing via the outside door handle electronics discontinued from 09/2011

From 09/2011, it will no longer be possible to close the soft top via the outside door handle electronics on vehicles with optional equipment "Comfort Access" (SA322). The other functions of the optional equipment "Comfort Access" remain unchanged.

NOTICE: Bear the national version in mind.

The opening and closing of the soft top is encoded for the specific market.

Brief component description
The following components are described for the fully automatic soft top:

Sensors for detection of the soft top position
9 hall effect sensors in total, 1 microswitch and 2 incremental sensors deliver a signal to the convertible top module (CVM).

- Hall effect sensors [1, 3, 4, 6 to 9, 11]
The hall effect sensors deliver the signals to the convertible top module (CVM) which uses this information to determine the position of the soft top.

- Incremental sensor in electric motor for cowl panel lock drive and rear-window drive [2 and 5]
The incremental sensor delivers signals regarding the direction of rotation, speed and position of the electric motor.

- Switch for convertible top compartment floor [10]
This microswitch ensures that the convertible-top compartment floor is lowered. When the convertible-top compartment floor is lowered, the microswitch is connected to the ground. In this case there is no convertible top movement (blocking condition).

NOTICE: No short circuit detection

A short circuit, or disconnection in the line, to the switch for convertible top compartment floor is not detected.

CVM: Convertible-top module
The convertible top module (CVM) is the central control unit for all soft top functions. The convertible top module controls all the electric and hydraulic functions of the soft top.
The convertible top module is connected at the K CAN2. This means that Information such as the ambient temperature and driving speed is received via K CAN2. On opening and/or closing the soft top, the convertible top module sends a signal to the Car Access System (CAS). The Car Access System is the master control unit for the power window regulator. The Car Access System sends CAN messages to activate the footwell module (FRM) as well as the junction box electronics (JBE). The signal serves as a request to open or close the side windows. The rear-window drive that opens and closes the rear window activates the convertible top module directly.
The convertible top module is installed on the inner right side wall near the partition wall to the luggage compartment.
Under certain blocking conditions, the convertible top module cannot execute a convertible top movement (see 'System functions').

Switch for convertible top operation
The switch for soft top operation is in the centre console. The switch is connected to the convertible top module.
The switch cluster function is encoded for the specific market. Operate the soft top in the European version using the rocker switch integrated in the switch as follows:
- Pull and hold the rocker switch in this position to open the side windows, rear window and soft top.
- Push and hold the rocker switch in this position to close the side windows, rear window and soft top.

NOTICE: Bear the national version in mind.

US version: Pull and hold the rocker switch in this position to close the soft top. Push and hold the rocker switch in this position to open the soft top.

One red and one green function LED are built into the rocker switch. The convertible top module (CVM) activates the function LEDs.
- Green function LED
The green function LED lights up during an opening or closing movement to display a convertible top movement.

- Red function LED
The red function LED begins to flash if during release of the rocker switch the soft top or the soft top compartment lid is not in a small secure end position. A Check Control message also appears on the instrument panel.
Flashing of the red function LED does not indicate a fault. The flashing LED signals that the vehicle must not be driven in this state.
The red function LED lights up if the soft top is opened by a keystroke and a blocking condition is presented (e.g. convertible top compartment floor not in lower section). The red function LED also lights up during closing of the soft top and presence of a blocking condition (e.g. tailgate open).

If the rocker switch is released during movement, the convertible top movement stops straight away. In addition, the opening or closing action of the side windows and the rear window also stops straight away.

Soft top drive
The soft top drive (electric motor with hydraulic pump and valve block) drives all convertible top movements via 3 cylinder pairs.
- One cylinder pair moves the main pillars of the soft top.
- One cylinder pair moves the fins.
- One cylinder pair moves the soft top compartment lid.

The direction of movement of the soft top (OPEN to CLOSED) is controlled by 2 relays. The cylinders are supplied with hydraulic fluid by a hydraulic pump (3 pistons) with 2 directions of rotation. The direction of movement is determined by reversing the hydraulic pump's direction of rotation.
The hydraulic pump is installed in the hydraulic unit. The system pressure is limited to 190 bar by 2 pressure limiting valves. The two relays and 3 hydraulic valves used for control of the hydraulic system are also integrated in hydraulic unit. The hydraulic pump only operates during the soft top movement.
The convertible top module has its own overheating protection to prevent the electric motor from overheating. The temperature of the electric motor is continuously calculated based on the operating period (operating time and rest phase) via a thermal model in the convertible top module. Once a certain temperature threshold has been exceeded, the convertible top module switches the electric motor off. The soft top can be moved again after a cooling-down period.
To protect the drive, every activation of the electric motor is terminated by the convertible top module (CVM) once a certain time has elapsed (8 minutes at the most).
If the soft top is opened completely or has been closed, the entire hydraulic system is depressurised.
If the convertible top movement is interrupted, the soft top compartment lid closes automatically after 8 to 10 minutes (after roughly 30 seconds if operated using the ID transmitter). To do this, the convertible top module supplies current to a specific changeover valve in the hydraulic unit on a rotational basis (cyclical actuation).

Cowl panel lock drive
An electric motor with gearbox locks or unlocks the soft top with cowl panel at the windscreen frame. The Convertible Top Module (CTM) activates the drive.
The drive is arranged in the centre. A rotating disk and thrust rods move the catches to the right and left.
An incremental sensor on the electric motor and a hall effect sensor are installed for identifying the position (cowl panel locked or unlocked).
The incremental sensor at the electric motor communicates the direction of rotation and increments of the electric motor to the convertible top module. After a certain number of increments, the convertible top module detects that the retaining hooks have unlocked.
The hall effect sensor signals to the convertible top module that the soft top has locked at the cowl panel.
When the convertible top module receives the "cowl panel locked" signal, it calibrates the starting value of the incremental counter.

The convertible top module has its own overheating protection to prevent the electric motor from overheating. The temperature of the electric motor is continuously calculated based on the operating period (operating time and rest phase) via a thermal model in the convertible top module. Once a certain temperature threshold has been exceeded, the convertible top module switches the electric motor off. The rear-window drive can be operated once again following a cooling-down period.
To protect the drive, every activation of the electric motor is terminated by the convertible top module (CVM) once a certain time has elapsed (30 seconds at the most).

Instrument panel: Instrument panel
The instrument panel delivers the ambient temperature (bus signal). The instrument panel uses the Check Control symbol to display the Check Control messages for the soft top.

FRM: Footwell module
The footwell module activates the front power window regulators. To open the soft top, the front side windows must be lowered (bus signal from convertible top module).
The footwell module supplies the locator lighting of the soft top operation switch with terminal 58g via a direct line.

JBE: Junction Box Electronics
The junction box electronics activate the rear power window regulators. To open the soft top, the rear side windows must be lowered (bus signal from convertible top module).
The junction box electronics deliver the signal as to whether the luggage compartment lid is closed (bus signal).

ICM: Integrated chassis management
The Integrated Chassis Management coordinates longitudinal and transverse dynamic control functions. The Integrated Chassis Management outputs signals to communicate the current dynamic handling characteristics to all vehicle systems.
The Integrated Chassis Management delivers the speed signal (bus signal).

CAS: Car Access System
The Car Access System is the master control unit for the power window regulators. Following a request from the convertible top module (CVM), the Car Access System ensures that the side windows are opened or closed. The Car Access System also prevents the tailgate from being opened and prevents any movement of the power window regulator with the soft top in an intermediate setting.
The Car Access System is the master control unit for the terminal control. The Car Access System activates terminal 15N and terminal 30B among others. The rear power distribution box supplies the convertible top module (CVM) with terminal 30B and terminal 15N.
Depending on the vehicle equipment, the control unit function for the comfort access system may also be integrated in the Car Access System.

System functions
The following graphic shows the soft top system network (this schematic diagram bears no relation to installation space).

The following system functions are described for the automatic soft top:
- Opening and closing the soft top
- Convenient operation
- Automatic engine start-stop function
- Check Control messages "
Opening and closing the soft top
The following preconditions must be met in order to open or close the soft top:
- Terminal R ON (when operated via Comfort Access)
- Terminal 15 ON (when operated via switch for soft top operation)
- Ambient temperature greater than -20 °C (e.g. -15 °C)
- Tailgate closed
- Driving speed less than 40 km/h
- Convertible top compartment floor lowered
- Battery voltage greater than 11.5 volts
- Temperature of hydraulic pump not too high
- Release by Car Access System (CAS) "

Automatic opening runs as follows:
- Side windows and rear window are lowered (if closed or in intermediate setting)
- The heated rear window is switched off (via the junction box electronics)
- The soft top is unlocked at the cowl panel
- The soft top compartment lid is opened
- The soft top is deposited in the soft top compartment
- The soft top compartment lid is closed and locked
- The side windows and rear window are closed

NOTICE: Bear the national version in mind.

Closing the side windows is coded on a country-specific basis.
Automatic closing of the soft top takes place in reverse order.

Convenient operation
The soft top in vehicles with the optional equipment (SA322) "Comfort Access" can be opened or closed via the ID transmitter.
The soft top can also be operated via the outside driver or front passenger door handle electronics as well as via the mechanical key in the door lock.

NOTICE: Convenient closing via the outside door handle electronics discontinued from 09/2011

From 09/2011, it will no longer be possible to close the soft top via the outside door handle electronics on vehicles with optional equipment "Comfort Access" (SA322). The other functions of the optional equipment "Comfort Access" remain unchanged.

Automatic engine start-stop function
If the combustion engine is started when the convertible top is moving (by the automatic engine start-stop function or via the start/stop button), the convertible top module interrupts activation of the opening or closing action. If the operating point continues to be operated, the convertible top movement resumes following the engine start.
If the combustion engine is stopped during convertible top movement (by the automatic engine start-stop function or via the start/stop button), the opening or closing action is maintained for as long as is requested by the operating point.

Check Control messages
It is not possible to open and close the soft top in certain situations. Corresponding Check Control messages are displayed in the instrument panel for this purpose.
In vehicles with the Central Information Display (CID), further explanations and handling instructions are provided for most Check Control messages in the Central Information Display.
The Check Control messages serve as additional information when the red light-emitting diode (LED) on the soft top operation switch lights up to indicate a fault.
A Check Control message is displayed every 5 seconds.

Notes for Service department

General notes

NOTICE: For emergency operation see repair instructions.

The emergency actuation is described in detail in the repair instructions.

IMPORTANT: No anti-trap mechanism for the rear window

The rear window has no anti-trap mechanism.

NOTICE: Maintenance-free hydraulic fluid

The hydraulic fluid does not have to be changed because the system is filled with life-time fluid. If, as a result of a leak, hydraulic fluid needs to be topped up, always use the approved grade of hydraulic fluid. Pour in hydraulic fluid only up to marking on oil reservoir.

NOTICE: If excessive noise is generated, bleed the hydraulic system

If there is a significant build-up of noise while the soft top is moving, the soft top must be opened and closed several times. This will automatically bleed the hydraulic system in the oil reservoir.

Diagnosis instructions

General notes
The "soft top initialization" service function must be run if one of the following components has been replaced:
- Soft top
- Convertible-top module
- Angle-of-rotation sensor for main pillar and/or angle-of-rotation sensor for fin

Notes on learning via switch for soft top operation
As well as teaching with the diagnosis, the closed position of the soft top can be taught via the switch for soft top operation. The soft top must only be partially opened beforehand in order to teach the position via the switch for soft top operation. It is enough if the soft top only opens slightly and travels to an intermediate setting (e.g. with fins slightly raised) then closes. Procedure:
- Close soft top.
- After closing the soft top, release the rocker switch mounted in the switch for soft top operation. Operate it again within 5 seconds and for approximately 30 seconds (in position close soft top).

The user will not be aware of the processes taking place in the system during teaching or during the 30 second period (a function LED will not light up and there will be no convertible top movement, for example).
We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.