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 (CVM). All microswitches and hall effect sensors are supplied with voltage from the convertible top module (CVM) and have a diagnostic capability.

The button signals from the soft top operation switch are read directly in to the convertible top module (CVM). In accordance with the request signals (open soft top or close soft top), the convertible top module (CVM) activates the soft top drive and, depending on the series, the rear-window drive. In addition, the convertible top module (CVM) controls the electric motor for the cowl panel lock drive.

Depending on the series, there is a soft top operation switch with and without a function indicator light.

• Soft top operation switch with function indicator light

  The convertible top module (CVM) activates the function LEDs (green and red) on the soft top operation switch. 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 (CVM) 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.

When opening and closing the soft top, the convertible top module (CVM) issues a message to the data 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 (CVM) issues information to the instrument cluster in the form of Check Control messages.

Fig 1: Identifying Convertible Top Module And Plug Connection

Courtesy of BMW OF NORTH AMERICA, INC.