Safety functions

When the motor continues to run in a single direction for a specific period (roughly 15 seconds), the roof function center (FZD) deactivates the drive unit.

Operation of the drive unit's overheating protection is governed by calculations carried out in the roof function center (FZD). This process is supported by a temperature sensor mounted on the roof function center's printed circuit board, where it registers the ambient temperature. The roof function center (FZD) calculates current temperature based on the drive units' operating period. Once the temperature in a drive unit reaches a specified threshold the roof function center (FZD) deactivates it. The warm-up and cooling-down periods are stored in a temperature model in the roof function center (FZD).

The current temperature is stored before the roof function center (FZD) reverts to its rest state. The temperature of the electric motor will be adjusted to ambient temperature when driving readiness is established again.

Closing the slide/tilt sunroof is still possible even if the overheat cut-out is active.

Seizure is recognized when no pulses from the hall effect sensors are received for longer than 500 milliseconds while travel motion is being executed. The roof function center (FZD) deactivates the voltage supply to the drive unit where seizure occurs.

Both the glass slide/tilt sunroof panel and the sliding headliner are equipped with closing force limiters. Activation of the closing force limiter is based on electrical power consumption and the signals from the hall effect sensor over a given period of time. The roof function center (FZD) responds to conditions in which fingers could potentially become trapped by stopping the corresponding drive unit and then reversing its motion. That opens the glass slide/tilt sunroof panel or sliding headliner again (by about 20 centimeters), thereby releasing the obstruction.

The "panic mode" is only available provided that a valid enable signal has been received from the Car Access System (CAS).

In panic mode the glass slide/tilt sunroof panel is closed with maximum power. Panic mode is initiated as follows using the sunroof switch:

1. Press "close" to beyond the detent-engagement point and hold it in place In the case of a trap the glass slide/tilt sunroof panel reverses by approx. 1 centimeter.
2. Release slide/tilt sunroof switch
3. Press "Close" and hold it in place.

Releasing the switch and then pressing it again is necessary because the reduced closing force limiter is still active the first time the switch is pressed (Emergency mode). Pressing the switch past "Close" a second time within a short space of time closes the glass slide/tilt sunroof panel with maximum power. The panic mode is available for activation at driving speed of up to 16 kilometers per hour. The panic mode can be activated from both the "raised" and the "open" positions.

Operation of the slide/tilt sunroof is stopped or prevented while the engine is being started. The Car Access System (CAS) transmits the status "Terminal 50 on". The load cutoff minimizes loads imposed on the battery during starting. Once the engine has been started, the slide/tilt sunroof can be operated again.