Convertible Top: Description and Operation

Fully Automatic Soft Top

Opening and closing the electrohydraulic Soft Top are fully automatic. Opening and/or closing the Soft Top takes around 22 seconds. If required, this can also be done when the vehicle is moving at low speed (up to 40 km/h). Here, the Soft Top is moved by hydraulic cylinders. An electric motor unlocks and locks the Soft Top at the cowl panel.
After opening, the Soft Top is stored in the soft top compartment. Subsequently, the Soft Top cover is closed automatically. The Soft Top can be operated using 2 buttons in the centre console switch cluster.

Brief description of components
The following components are described for the fully automatic Soft Top:

Sensors for detection of the Soft Top position
In total, 8 Hall sensors, 1 micro-switch as well as 1 incremental transducer are installed as sensors for the Soft Top Module (CVM).







- Hall sensors [2 to 7 and 9 to 10]
The Hall sensors deliver the signals to the Soft Top Module (CVM). The CVM uses the signals to determine the position of the Soft Top.
- Incremental transducer in the drive for securing the Soft Top [1]
The incremental transducer is integrated in the drive for the Soft Top unlocking mechanism. The incremental transducer monitors the revolutions of the drive. Here, the following states of the interlock are distinguished:
'closed', 'intermediate position', 'opened'
- Switch for the Soft Top compartment floor [8]
This micro-switch ensures that the Soft Top compartment floor is lowered. With the Soft Top compartment floor not lowered, the micro-switch is short-circuited to earth. If this condition is not met, the Soft Top is not opened (block condition).

NOTE: No short circuit recognition.

A short circuit of the lead to the switch for the Soft Top compartment floor is not detected by the Soft Top Module (CVM).

CVM: Soft Top Module
The Soft Top Module (CVM) controls all the electric and hydraulic functions of the Soft Top. The Soft Top Module is connected on the K-CAN.
The Soft Top Module is fitted at the partition wall to the luggage compartment.
Under certain block conditions, the CVM cannot execute a Soft Top movement (see 'System functions').







Button for operation
The centre console switch cluster is equipped with 2 buttons ('open Soft Top' and 'close Soft Top') for Soft Top operation. The centre console switch cluster (SZM) is connected to the heating / air-conditioning control panel (= control unit).







There is a red and green function LED above the two buttons. The control LEDs are activated by the Soft Top Module (CVM) via the K-CAN.
The green LED lights up during Soft Top movement. The red LED starts to flash if the Soft Top or Soft Top cover is not in a safe end position when the button is released.
The red LED flashing does not indicate a fault. The flashing LED is intended to indicate that in the vehicle must not be driven in this status.
The red LED lights up if the Soft Top is opened by pressing a button and there is a block condition (e.g. Soft Top compartment floor not down).
The red LED also lights up on closing the Soft Top if there is a block condition (e.g. luggage compartment lid or temperature).
The two control buttons are designed with 2 double contacts (make contact to earth). A direct line leads to the CVM and reports a general operation request. The second line reports the direction to the control unit for the heater/air conditioning system (IHR, IHKR, IHKA). Subsequently, the signal is sent via K-CAN to the CVM. This means that an operation request is executed with a delay. If the button is released during the movement, the Soft Top movement or side window movement stops immediately.

Soft Top drive unit
The Soft Top drive unit (motor with hydraulic pump and valve block) drives all Soft Top movements via 3 cylinder pairs.
One cylinder pair each operates the:
- Main pillars of the Soft Top
- Tensioning bars of the Soft Top
- Soft Top compartment cover







The direction of movement of the Soft Top (OPEN or CLOSED) is controlled by 2 relays.
The cylinders are supplied with oil by a hydraulic pump (3 pistons) with 2 directions of rotation. The reversal of the direction of rotation of the hydraulic pump determines the direction of movement.
The hydraulic pump (max. 200 bar) is installed in the hydraulic unit. The two relays as well as the 3 hydraulic valves for the hydraulic control are also integrated in the hydraulic unit.
The hydraulic unit is secured with a slow-response fuse of 50 Amperes.
A "pump protection counter" is implemented in the Soft Top Module (CVM) to protect the hydraulic unit.
The hydraulic pump only operates during the Soft Top movement. In the event of failure, emergency actuation is possible.







The hydraulic unit is installed in the rear right of the luggage compartment. For acoustic reasons, this is maximum distance away from the driver.

Drive unit for locking cowl panel
An electric motor with gear locks and unlocks the Soft Top with cowl panel at the windshield frame. The Soft Top Module (CVM) activates the drive.
The drive is arranged in the centre. A rotating disk and thrust rods move the catches to the right and left. The Hall sensor 'cowl panel locked' monitors the interlock.







The following other control units are involved in the function of the Soft Top:

KOMBI: Instrument cluster
The instrument cluster delivers the outside temperature (bus signal).
The instrument cluster displays via the Check Control messages for the Soft Top via Check Control symbol.

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) actuates the rear power windows. To open the Soft Top, the side windows must be lowered (bus signal from CVM).
The junction box electronics deliver the signal as to whether the luggage compartment lid is closed (bus signal). The distribution box in the junction box supplies the Soft 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 unit 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 Soft Top in its intermediate position.
The Car Access System (CAS) controls convenience opening of the Soft Top. The signals from the remote control are received by the FBD receiver and forwarded to the CAS.
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 Soft Top:
- Opening and closing the Soft Top
- Convenience operation
- Check Control messages

Opening and closing the Soft Top
To open and close the Soft Top, the following conditions must be met:
- Terminal R ON
- Outside temperature above -12 °C
- Luggage compartment lid closed
- Driving speed less than 40 km/h
Driving speed lower than 50 km/h:
completion of closing and opening of the Soft Top is possible up to the end position.
Driving speed higher than 50 km/h:
the Soft Top comes to a standstill.
Driving speed higher than 70 km/h:
fault code memory entry A69A: speed in Soft Top position greater than permitted.

- Soft Top compartment floor at bottom
- Battery voltage greater than 11.5 Volts
- Fewer than 5 opening and closing operations in succession (pump protection inactive)
- Enable from the Car Access System (CAS)

Automatic opening runs as follows:
- The side windows are lowered (if closed or in intermediate position)
- The Soft Top is unlocked at the cowl panel.
- The heated rear window is switched off (via the junction box electronics)
- The Soft Top cover is unlocked and opened
- Soft Top is stored in the Soft Top compartment
- The Soft Top cover is closed and locked
- Windows are closed

NOTE: 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.

Convenience operation
The Soft Top can be operated using the remote control as well as the mechanical key in the door lock. In the case of vehicles with optional extra "Comfort Access", the Soft Top can be opened and closed via the identification sensor.
The convenience functions via the remote control are country-specific.
Conditions for operation with the remote control or identification sensor with Comfort Access (optional extra 322)







Check Control messages
In certain situations, it is not possible to open or close the Soft 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.
The Check Control messages provide a better explanation of the red LED on the button, which lights up in the event of a fault.
Any Check Control message that is present 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.

IMPORTANT: There is no anti-trapping mechanism for the rear power windows.

The rear power windows have no anti-trapping mechanism.
This means there is also no one-touch control function for closing the rear windows.

NOTE: No convenience closing via the outside door handle electronics.

On vehicles with Comfort Access, convenience closing is not possible using the outside door handle electronics.
Convenience closing is run via lock cylinders.

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 mark 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 Soft Top.

If the BMW diagnosis system triggers the rollover protection, the Soft Top must be opened first of all. Otherwise, the Soft Top will be destroyed.
Mechanical triggering is not possible on the E88.

IMPORTANT: Special feature of the button to open or close the Soft Top.

Fault code A69B "Line release / stop" is stored under the following conditions:
- Terminal R On while the button is pressed
- After Soft Top movement concluded, button pressed for longer than 20 seconds

This enables detection of a short circuit to earth on this line.
The fault code memory entry can also occur due to incorrect operation: e.g. passenger presses 'open Soft Top' and driver switches terminal R On.
In this case, the fault code is stored as "not present". The Soft Top is temporarily without function. After opening once using the button, the roof is operational again.

Notes on coding / programming
After replacement, the Soft Top Module (CVM) must be recoded.

National versions
Bear in mind the different national versions for the convenience functions:
see section "Convenient operation and convenience function for loading and unloading the luggage compartment".
No liability can be accepted for printing or other errors. Subject to changes of a technical nature.