Convertible Top Control Module: Description and Operation
Fully Automatic Convertible Top
As series standard, the MINI Convertible is equipped with a fully automatic, electrohydraulic convertible top. It is operated by means of a button above the interior mirror. Opening and/or closing the convertible top takes around 15 seconds (with side windows, approx. 18 seconds). A folding sun roof is integrated in the convertible top. To open the convertible top, the folding sun roof must first be fully opened. Pulling the button again opens the convertible top.
Loading assistance: Before setting down, the tensioning bar must be locked by hand on both sides.
Pulling the button for convertible top operation towards the rear opens the folding sun roof first. Opening up to the maximum opening position is possible at a speed of up to 120 km/h. Above 120 km/h, the folding sun roof remains in the position it last assumed (until the vehicle has been moving slower than approx. 115 km/h for 2 seconds). The drive for the folding sun roof is arranged in the center. Two bowden cables move the gates on the right and left.
If the button is operated again after opening the folding sun roof, all the windows are lowered simultaneously. The cowl panel is then unlocked and the convertible top opened. The complete convertible top is stored and locked in the stored state. The window are closed completely. Opening the convertible top is possible at a speed of up to 30 km/h. Above this speed, the convertible top movement is stopped. The instrument cluster issues a Check Control message. The green LED starts to flash. As of a speed of 50 km/h, a fault memory entry is made. The convertible top is moved by hydraulic cylinders. The are supplied with oil by a two-directional hydraulic pump across a short pressure line from the luggage compartment area. The reversal of the direction of rotation of the pump determines the direction of movement.
Brief description of components
The following components are described for the fully automatic convertible top:
Sensors for detection of the convertible top position
In total, 5 Hall sensors, 1 micro-switch as well as 2 incremental transducers are installed as sensors for the convertible top module (CVM).
- Hall sensors
The Hall sensors help the Convertible Top Module (CTM) to detect the position of the convertible top. This means that after loss of terminal 30 or emergency actuation the convertible top can still be operated without re-initialization.
- 2 Incremental transducer in the cowl panel lock drive and folding sun roof
The incremental transducer is integrated in the locking drive and folding sun roof. The incremental transducers monitor the direction and speed of the drive.
- Microswitch, rear window shelf down
This micro-switch ensures that the back shelf (= rear window shelf) is lowered. With the back shelf lowered, the micro-switch is short-circuited to ground. If this condition is not met, the convertible top is not opened (block condition). In the event of a malfunction, the micro-switch generates a fault memory entry.
NOTE: No short circuit recognition.
A short circuit of the lead to the micro-switch is not detected by the Convertible Top Module (CTM).
CVM: Convertible top module
The convertible top module (CVM) controls all the electric and hydraulic functions of the convertible top. The convertible top module is connected on the K-CAN.
The convertible top module is installed at the rollover protection.
Under certain block conditions, the CVM cannot execute a convertible top movement (see System functions).
Convertible top button
The button is integrated on the cowl panel in the roof control panel.
Pull button towards the rear: the convertible top opens.
Press button forwards: the convertible top closes. A green LED as function indicator is integrated in the roof control panel.
The LED only lights up with convertible top movement, not with movement of the folding sun roof.
LED lights up:
- during convertible top movement if no block condition is set
LED flashes:
- Convertible top in a safe end position (a Check Control message also appears in the instrument cluster)
- Convertible top in safe end position and one or a number of block conditions have been set (a yellow Check Control symbol also appears in the instrument cluster: e.g. back shelf not lowered or driving speed greater than 30 km/h)
Convertible top drive unit
The convertible top drive unit (motor with hydraulic pump and valve block) drives all convertible top movements via cylinder pair. The cylinder pair moves the main pillars of the convertible top.
The direction of movement of the convertible top (OPEN or CLOSED) is controlled by 2 relays. The cylinders are supplied with oil by a hydraulic pump with 2 directions of rotation. The reversal of the direction of rotation of the hydraulic pump determines the direction of movement.
The hydraulic unit is secured with a slow-response fuse of 40 Amperes.
A "pump protection counter" is implemented in the convertible top module (CVM) to protect the hydraulic unit.
The hydraulic pump only operates during the convertible top movement. In the event of failure, emergency actuation is possible.
The hydraulic unit is installed in the rear left of the luggage compartment. The relays are also in the rear left of the luggage compartment.
Drive unit for lock and folding sunroof
An electric motor with transmission locks and unlocks the convertible top with cowl panel at the windshield frame. At the same time, this drive moves the folding sun roof. The convertible top module (CVM) activates the drive.
The drive is arranged in the center. The gates on the right and left are moved via 2 coiled cables, thus driving the folding sun roof. When the folding sun roof is open, the catches also open.
NOTE: The drive has an additional function.
When the convertible top is opened, the drive locks the stored convertible top. The purpose of this function is crash detent. In the event of a crash, the stored convertible top cannot fold forwards.
The following other control modules are involved in the function of the convertible top:
KOMBI2: Additional instrument
The additional instrument (KOMBI2) delivers the outside temperature (bus signal).
The additional instrument displays the Check Control messages for the convertible top via the Check Control symbol.
FRM: Footwell Module
The footwell module (FRM) activates the front power windows. To open the convertible 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 distribution box in the junction box supplies the convertible top module (CVM) with terminal 30g.
In addition, the CVM is supplied with terminal 15 by 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 module for the power windows.
When requested by the CVM, the CAS ensures that the side windows are lowered and/or raised. The CAS also prevents opening of the luggage compartment lid and power window movement with the convertible top in its intermediate position.
The Car Access System (CAS) controls convenience opening of the convertible top. The signals from the remote control are received by the FBD receiver and forwarded to the CAS (currently not for Comfort Access).
Convenience opening and convenience closing via the lock cylinders of the driver's door: The CAS receives the signal from the footwell module (FRM).
System functions
The following system functions are described for the automatic convertible top:
- Opening and closing the convertible top
- Conditions for opening and closing
- Pump protection counter
- Overheating protection for drive lock and folding sun roof
- Convertible top opening duration display
- Check-control messages
Opening and closing the convertible top
Opening and Closing The Convertible Top:
Opening and Closing The Convertible Top:
Conditions for opening and closing
Conditions For Opening and Closing:
Pump protection counter
A pump protection counter has been implemented to fully safeguard the hydraulic pump. The pump safeguard is active and the function inhibited after an operation time of 3.5 minutes. A ramp function enables an initial shortened operating period after 1.1 minutes. The full operating time of 3.5 minutes is available after a waiting period of 15.5 minutes.
When the pump protection is active, a fault is entered in the fault memory.
Overheating protection for drive lock and folding sun roof
The function is inhibited after an operation time of more than 2.20 minutes. The full operating time is available after a waiting period of 50 seconds. It is always possible to close the convertible top. When the overheating protection is active, a fault is entered in the fault memory.
Convertible top opening duration display
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 convertible top is opened. Counting only starts when the convertible top is fully opened and only if the engine is running. Two digital counters can be called up in the 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 convertible 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 change 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
In certain situations, it is not possible to open or close the convertible top. Here, the corresponding Check Control messages are displayed in the instrument cluster.
In the case of vehicles with a Central Information Display (CID), a text message and supplementary instructions are displayed.
A Check Control message is displayed every 5 seconds.
Notes for Service department
General information
NOTE: Emergency actuation, see Repair instructions.
The emergency actuation is described in detail in the repair instructions.
NOTE: Maintenance-free hydraulic fluid.
Because of its life-time oil filling, the hydraulic fluid does not have to be renewed. If the hydraulic fluid has to be topped up due to leakage, only the approved hydraulic fluid may be used. Only add hydraulic fluid up to the marking on the oil reservoir.
NOTE: If excessive noise is generated, bleed the hydraulic system.
If excessive noise is generated while the hardtop is moving, the hardtop must be opened and closed several times. This will automatically bleed the hydraulic system in the oil reservoir.
Diagnosis instructions
IMPORTANT: When working on the rollover protection system, open the convertible top.
If the BMW diagnosis system triggers the rollover protection, the convertible top must be opened first of all. Otherwise, the convertible top will be destroyed.
Mechanical triggering is not possible on the R57.
Notes on encoding / programming
After replacement, the convertible top module (CVM) must be re-encoded.
No liability can be accepted for printing or other faults. Subject to changes of a technical nature.