Convertible Top: Description and Operation

Convertible-Top Module

Convertible-top module
The convertible top module (CVM) is the central control unit for all soft top functions.
The convertible top module is installed on the inner right side wall near the partition wall to the luggage compartment.

Functional description
The soft top module (CVM) controls all the electric and hydraulic functions of the soft top.
The different positions of the soft top are detected by microswitches and hall effect sensors and reported to the convertible top module. All microswitches and hall effect sensors are supplied with power from the convertible top module and are capable of diagnosis.
The switch signals for soft top operation are read in directly to the convertible top module. Corresponding to the request signal (open or close soft top), the convertible top module activates the soft top drive and rear-window drive. In addition, the convertible top module controls the drive unit for the cowl panel lock drive.
The convertible top module also activates the function LEDs (green and red) on the switch for the convertible top movement. The green function LED lights up during convertible top movement. The red function LED begins to flash if during release of the button the soft top or the soft top compartment lid is in a small secure end position.
Flashing of the red function LED does not indicate a fault. The flashing LED draws attention to the fact that the vehicle must not be driven in this state.
The red function LED lights up when the soft top is opened or closed by a keystroke and a blocking condition is present (e.g. ambient temperature too low or driving speed too high).
The convertible top module is a bus user. Information is thus received for the system function (e.g. ambient temperature, driving speed and status of the tailgate) via the bus.
For opening and closing the soft top the convertible top module issues a message to the bus. As part of the system function the side windows are lowered during the opening procedure for example.
In certain situations, the convertible top module provides information in the instrument panel as Check Control messages.







Structure and inner electrical connection
The convertible top module (CVM) controls and monitors the individual components. In addition, fault entries are stored.
The convertible top module is connected at the K CAN2. The rear power distribution box supplies the convertible top module with power with terminal 30B and terminal 15N.
For the connection to the vehicle electrical system and the individual system components the convertible top module has 2 plug connections (26-pin and 41-pin).







Pin assignments
The graphics above show only the supply and bus connection. The current pin assignment is recorded on the wiring diagrams in the ISTA diagnosis system (Integrated Service Technical Application). Click on the component code in the wiring diagram to activate the "Installation location" and "Pin assignment" tabs.

Nominal values

Observe the following setpoint values for the convertible top module (CVM):

Size Value
Supply voltage 9 to 16 V
Temperature range -40 to 80 °C

Diagnosis instructions

Failure of the component
In the event of a communication failure to the convertible top module (CVM), carry out the standard checks (global procedure). If there is an internal control unit fault, the following behaviour is to be expected:
- Fault entry in the convertible top module (CVM)
- Check Control message in the instrument panel

After replacement, the soft top Module (CVM) must be encoded again and initialised.
We can assume no liability for printing errors or inaccuracies in this document and reserve the right to introduce technical modifications at any time.