Semi-Automatic Convertible Top
Semi-Automatic Convertible Top
Semi-automatic Convertible Top
The MINI Roadster is equipped with a manually operated soft top as standard. A semi-automatic convertible top (SA398) is available as optional equipment. Both versions are manufactured by Webasto Edscha.
The soft top folds down z-shaped and uses the front soft top bow as soft top compartment lid.
The integrated electric heated rear window removes the condensation. The rear window can only be switched on when the soft top is closed. When the soft top is opened while the heated rear window is switched on, the heated rear window will switch off automatically.
Special features of the semi-automatic convertible top:
- It is not possible to open or close the soft top while the vehicle is being driven.
- The automatic convertible top movement during opening lasts for approximately 6 seconds, when closing approximately 7 seconds.
- The opening and closing of the soft top is also ensured during an automatic engine shutdown through the automatic engine start-stop function. While the engine is started, the convertible top movement will be stopped briefly and then continued. The button for the soft top does not have be pressed again.
Brief component description
The following components are described for the semi-automatic soft top:
Sensors to identify the position of the soft top
The manually operated soft top has a hall effect sensor on the right main pillar soft top control lever. The hall effect sensor detects when the soft top is completely open.
The hall effect sensor works touchless and it is not sensitive to temperature fluctuations or vibrations. The junction box electronics (JBE) teach in the hall effect sensor.
The semi-automatic convertible top has 3 microswitches. The 3 microswitches on the left side of the soft top have been taught in by the convertible top module (CVM).
- The microswitch at the left roof soft top steering lever records the raised position of the soft top. The soft top is thereby ready for electric operation and stowage.
- The centre microswitch at the left main pillar records the stowed (opened) position of the soft top.
- The lower microswitch at the left main pillar records the closed position of the soft top.
CVM: Convertible-top module
The soft top Module (CVM) controls all the electric and hydraulic functions of the soft top. The convertible top module is connected on the K-CAN.
The convertible top module (CVM) is stored in the rear left luggage compartment.
Under certain block conditions, the CVM cannot execute a soft top movement (see 'System functions').
Soft top button
The button is integrated in the cowl panel in the roof operating unit. Pull button backwards: the soft top opens. Push button forwards: the soft top closes.
The button for the soft top is only available with the semi-automatic convertible top in the roof operating unit. The functions reading light and interior light were consolidated in the two outer rocker switches to maintain space for the additional rocker switch.
If the button is released while opening the soft top, the movements of the soft top and/or side windows will be interrupted immediately. Pressing the button again will resume the movements. When the button is released before the side windows are completely closed, the opening procedure may be continued within 10 seconds by pressing the button again (stop light).
Soft top drive
The soft top drive (hydraulic unit: The pump motor with hydraulic pump and valve block) drives all soft top movements via cylinder pair. The hydraulic cylinders affect the main control lever of the soft top frame. The hydraulic cylinders can be charged with pressure from the piston side and from the rod side. The operating direction of the hydraulic cylinder is contingent on the direction of rotation of the hydraulic pump. No corresponding valves are therefore required. The entire hydraulic unit is located with space saving design in the luggage compartment under the front tray in the luggage compartment.
The direction of movement of the soft top (OPEN to CLOSED) is controlled by 2 relays.
The hydraulic unit is safeguarded by a slow-acting 40-amp fuse. To protect the hydraulic unit, an overheating protection is integrated in the convertible top module (CVM).
The hydraulic pump only operates during the soft top movement. In the event of failure, emergency actuation is possible.
Associated hydraulic circuit diagram:
Cowl panel lock drive and support pedestal
The retaining hooks are moved by the locking lever through the pushrods to lock or unlock the front soft top bow with the windscreen frame (cowl panel).
When the soft top is completely opened the front soft top bow is placed on the support pedestal.
For vehicles with manually operated soft top, the front soft top bow is also locked on the support pedestal. The stowage lock button that is located on the trim panel between the rollover bars can be used to unlock the front soft top bow.
For vehicles with semi-automatic convertible top, the front soft top bow will not be locked, but it will be retained by the pressure in the hydraulic system through the hydraulic cylinders.
The following other control units are involved in the function of the soft top:
KOMBI2: auxiliary instrument
The auxiliary instrument (KOMBI2) delivers the ambient temperature (bus signal). The auxiliary instrument uses the Check Control symbol to show the Check Control messages relating to the soft top.
FRM: Footwell module
The footwell module (FRM) activates the front power windows. To open the soft top, the side windows must be lowered (bus signal from CVM).
JBE: Junction Box Electronics
The junction box electronics (JBE) deliver the signal as to whether the luggage compartment lid is closed (bus signal). The power distribution box in the junction box supplies the soft top module (CVM) with electrical power (terminal 30g). In addition, the CVM is supplied by terminal 15 from the Car Access System (CAS). If, for example, the power supply from the junction box is interrupted, adequate communication with the BMW diagnosis system is still possible.
CAS: Car Access System
The CAS is the master control unit for the power windows. Following a request from the CVM, the CAS ensures that the side windows are opened or closed as the case may be. The CAS also prevents opening of the luggage compartment lid and any power windows operation with the soft top in an intermediate setting.
The Car Access System (CAS) controls convenience opening of the soft top. The signals from the remote key are received by the FBD receiver and forwarded to the CAS.
System functions
The following system functions are described for the semi-automatic convertible top:
- Conditions for opening and closing
- Overheating protection
- Convertible top opening time display (optional equipment)
- Check Control messages
Conditions for opening and closing
- Vehicle stationary
- Terminal R ON and doors closed
- Battery voltage between 10.5 and 16 volts
- Temperature of the pump motor is not too high
- Ambient temperature above - -10 °C
Overheating protection
The temperature of the pump motor will be recorded by the convertible top module (CVM) via calculation model. The pump motor can run for approx. 3 minutes without interruptions. Once the pump motor has cooled, soft top can be operated again.
Convertible top opening time display (optional equipment)
The convertible top opening duration display is on the left beside the rev counter on the steering column. The display is only activated if the Soft Top is opened. Counting only starts when the Soft Top is fully opened and only if the engine is running. Two digital counters can be called up in the on-board computer display. The four-digit counter can be reset using the trip distance reset button. The six-digit counter can only be reset by means of a corresponding diagnosis instruction.
The soft top opening duration display shows hours and minutes. An LED is activated each hour on the hour. Minutes are displayed by the pointer on a scale of 0 to 60. A maximum of 7 hours can be displayed (6 LEDs and one pointer revolution). Following this, the display is reset automatically and the display cycle starts again from the beginning. The switch to a new display cycle is indicated by the flashing LEDs.
The display is also reset when the four-digit resettable counter overruns. In this case, the display cycle starts again from the beginning after only 2 hours (1 LED and one pointer revolution). The special feature of this is that 98 hours can be displayed in 14 cycles with a respective duration of 7 hours. The remaining difference to the overrun corresponds to these 2 hours.
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. On vehicles with a central information display (CID), a text message is displayed together with a supplementary set of instructions.
A Check Control message is displayed every 5 seconds.
Notes for Service department
General notes
NOTICE: Emergency actuation
The emergency activation is described in the repair instructions.
Notice: Zero-maintenance 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.
We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.