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Electric panoramic sliding sunroof, function - GF77.20-P-0003RF

MODEL 205, 253 with CODE 413 (Automatic panoramic sliding sunroof) 

Fig 1: Electric Panoramic Sliding Sunroof Block Diagram
G10134349Courtesy of MERCEDES-BENZ USA

Function requirements, general 

Electric panoramic sliding sunroof, general 

The front section of the panoramic sliding sunroof can be opened and closed again in the tilt or slide position. The extended roller sun blind is retracted previously. Operation occurs by means of the roof system switch on the overhead control panel control unit.

Overheating protection:

The panoramic sliding sunroof motor or the panoramic roof roller sun blind is protected against overheating by a software-based thermal protection in the panoramic sliding sunroof control unit. This temperature in the panoramic sliding sunroof motor and panoramic sliding sunroof roller sun blind motor is calculated in consideration of the voltage, current and duration of actuation as well as outside temperature. The front SAM control unit directly reads in the signal of the outside temperature sensor, calculates the outside temperature and sends it to the panoramic sliding sunroof control unit via interior CAN.

Detection of switch signals

Actuation of the roof system switch is clearly recognized only after t = 40 ± 10 ms. The maximum actuation time is t ≥ 20 s. After t ≥ 60 s, the system recognizes that the roof system switch is "stuck". A new actuation (triggered via the roof system switch) can only be performed again after detecting that the roof system switch is in the rest position.

IMPORTANT The panoramic sliding sunroof can be opened and closed using the comfort functions, which allow the panoramic sliding sunroof to be opened and closed centrally together with the side windows from one control point.

The electric sliding roof panoramic function comprises the following partial functions:

Function sequence for position monitoring 

The position is monitored by the panoramic sliding sunroof control unit by evaluating the signals from the following sensors:

The Hall sensors are positioned offset by 90° on the axle of the panoramic sliding sunroof roller sun blind drive unit and panoramic sliding sunroof motor. The position of the panoramic sliding sunroof and the roller sun blind is determined by counting the Hall sensor pulses. The zero position is set by normalization. The zero position is the position at which the panoramic sliding sunroof and roller sun blinds are closed. Blockage is detected if signals from the Hall sensors are no longer detected for a period of t = 160 ms during adjustment.

IMPORTANT If the Hall sensors fail, the roller sun blind can only be actuated in increments of t = 0.3 s. The panoramic sliding roof can only be closed with the hand crank.

Additional function requirements for normalizing 

Function sequence for normalization 

Normalization is the basis for the assignment of the current position to the position of the roller sun blind and/or the panoramic sliding sunroof recognized by the panoramic sliding sunroof control unit. To do so, the panoramic sliding sunroof and/or the roller sun blind must be closed completely.

Manually close the panoramic sliding sunroof and/or the roller sun blind using the roof system switch until the mechanical end stop has been reached. Next, operate the roof system switch again for at least t = 1 s. By evaluating the signals of the Hall sensors, the panoramic sliding sunroof control unit recognizes the blockage and sets the corresponding location counter to zero.

Denormalization is performed under the following conditions:

IMPORTANT The position of the panoramic sliding sunroof and the roller sun blind cannot be determined in the denormalized state. The function is then limited to manual closing or opening. Actuation can only be performed in steps of t = 0, 5 s each.

Function sequence for lockup recognition 

When the blockage has been recognized in the closing direction by the position monitoring, the roller sun blind motor and the panoramic sliding sunroof motor are first stopped and then actuated in the opposite direction (panoramic sliding sunroof normalized). When the blockage is recognized in the opening direction, the roller sun blind motor and the panoramic sliding sunroof motor are stopped and no longer actuated.

Additional function requirements for automatic reversing function 

Function sequence for automatic reserving function 

The automatic reversing function is based on the comparison of the current rpm of the panoramic sliding sunroof motor or the panoramic sliding roller sun blind motor with the rpm determined during a teach-in run or adaptation. If this comparison exceeds a certain limit value during a closing operation, this is detected as blockage by the panoramic sliding roof control unit.

IMPORTANT Teach-in mode: During teach-in mode, the panoramic sliding sunroof and the roller sun blind are moved through all closing operations in the normalized state. The panoramic sliding sunroof control module adapts to changes in the rpm resulting from increased sluggishness (e.g. dirt in the mechanical system).

If blockage is detected during opening, the panoramic sliding roof as well as the roller sun blind are stopped only. During closing, the panoramic sliding roof and the roller sun blinds are stopped when pinching is recognized and then reversed (moved in opposite direction).

With the automatic closing function, the roof is reversed by s = 145 mm.

During rain closing, the roof is reversed by s = 70 mm.

With the manual closing function, the roof is reversed by s = 20 mm.

Special case closing panoramic sliding sunroof manually If the roof system switch is actuated again in the closing direction within t = 2 s after the roof is reversed, greater force is applied to close the roof. The next attempt deactivates the automatic reversing function.

additional function requirements for opening/closing of roller sun blinds 

IMPORTANT The electronic ignition lock control unit sends the status of circuit 15 to the panoramic sliding sunroof control unit via the interior CAN. The left front door control unit directly reads in the status of the left front door rotary tumbler switch and sends it to the panoramic sliding sunroof control unit via interior CAN.

The right front door control unit directly reads in the status of the right front door rotary tumbler switch and sends it to the panoramic sliding sunroof control unit via interior CAN.

IMPORTANT When a front door is opened or closed during the run-on time, this triggers a restart of the run-on time.

Function schematic for opening/closing roller sun blind 

The roller sun blind can be opened and closed manually or automatically. The roller sun blind is opened or closed manually by actuating the roof system switch to the first catch. The roller sun blind is fully opened or closed automatically by actuating the roof system switch past the first catch.

The front SAM control unit reads in the status of the roof system switch via the roof LIN and sends it to the panoramic sliding sunroof control unit via interior CAN. The panoramic sliding sunroof control unit actuates the panoramic sliding sunroof motor according to the selected actuation direction. The automatic reversing function is active during closing.

Additional function requirements for opening/closing panoramic sliding sunroof 

IMPORTANT The electronic ignition lock control unit sends the status of circuit 15 to the panoramic sliding sunroof control unit via the interior CAN. The left front door control unit directly reads in the status of the left front door rotary tumbler switch and sends it to the panoramic sliding sunroof control unit via interior CAN.

The right front door control unit directly reads in the status of the right front door rotary tumbler switch and sends it to the panoramic sliding sunroof control unit via interior CAN.

IMPORTANT If the roller sun blind is closed, it is first fully opened before the panoramic sliding sunroof is opened.

Function sequence for opening/closing panoramic sliding sunroof 

The panoramic sliding sunroof can be opened and closed manually or automatically. The panoramic sliding sunroof is opened or closed manually for the time the request is active by actuating the roof system switch to the first catch. The panoramic sliding sunroof is fully opened or closed automatically by actuating the roof system switch past the first catch.

The front SAM control unit reads in the status of the roof system switch via the roof LIN and sends it to the panoramic sliding sunroof control unit via interior CAN. The panoramic sliding sunroof control unit actuates the panoramic sliding sunroof motor according to the selected actuation direction. The automatic reversing function is active during closing. The automatic reversing function is active within a limited range during opening (protection against pinching of glass cover rear edge/roof carrier or roof railing). Automatic opening and closing of the panoramic sliding sunroof is interrupted when the roof system switch is actuated again.

Function sequence for rain closing (except CODE 494 (USA version)) 

Rain closing comprises the following partial functions:

Additional function requirements for rain closing 

IMPORTANT The status of circuit 15 and the status of the central locking are sent by the electronic ignition lock control unit via the interior CAN to the panoramic sliding sunroof control unit.

Function sequence for rain closing 

The panoramic sliding roof is moved to the tilt position when it starts to rain.

Moistening the windshield is recognized by the rain/light sensor with additional functions. The rain/light sensor with additional functions reads in the signals of the rain sensor directly, evaluates them and sends the "Rain closing" request via rain/light sensor LIN, front SAM control unit and interior CAN to the panoramic sliding sunroof. The panoramic sliding sunroof control unit actuates the panoramic sliding sunroof motor. The panoramic sliding sunroof is adjusted to the tilt position. Monitoring is then no longer performed.

IMPORTANT Moreover, the rain closing feature is actuated if the run-on time (t = 6 h) has expired or the voltage or temperature is no longer within the operating range of the rain/light sensor.

IMPORTANT MODEL 205, 253

with CODE 413 (Automatic panoramic sliding sunroof)

with CODE 551 (Anti-theft warning system)

with CODE 882 (Interior motion sensor)

During rain closing, alarm triggering by the interior protection is suppressed to prevent the anti-theft alarm system (ATA [EDW]) from being triggered unintentionally.

Additional function requirements dynamic rain closing 

Function sequence for dynamic rain closing 

With dynamic rain closing, the raised automatically panoramic sliding roof lowers while driving and when it starts to rain. The lowering procedure depends on the vehicle speed and the intensity of the starting rain.

The rain/light sensor with additional functions reads in the signals of the rain sensor directly, evaluates them and sends the "Rain closing" request via rain/light sensor LIN, front SAM control unit and interior CAN to the panoramic sliding sunroof. The instrument cluster sends the vehicle speed to the panoramic sliding sunroof control unit via user interface CAN, electronic ignition lock control unit and interior CAN.

The panoramic sliding roof control unit evaluates the data and actuates the panoramic sliding roof motor.

IMPORTANT Dynamic rain closing can be interrupted by momentarily actuating the roof system switch and the panoramic sliding roof can be adjusted to any position.

Function sequence for speed-dependent tilt position 

The speed-dependent tilt reduction function prevents annoying wind noises at higher speeds. The instrument cluster sends the vehicle speed to the panoramic sliding sunroof control unit via user interface CAN, electronic ignition lock control unit and interior CAN.

The panoramic sliding roof control unit evaluates the vehicles peed, then the panoramic sliding roof is adjusted to the corresponding position.

IMPORTANT The speed-dependent tilt position can be activated using the diagnostic tester.

Additional function requirements for roof carrier recognition 

Function sequence for roof carrier recognition 

To prevent damage to the panoramic sliding sunroof during opening, an end stop is installed at the roof carrier. As soon as the panoramic sliding sunroof encounters this end stop during opening, the panoramic sliding sunroof control unit recognizes an obstacle due to the change in power consumption. Actuation of the panoramic sliding roof motor is interrupted.

Function sequence for memory function 

The memory function comprises the following partial functions:

Function sequence for roller sun blind memory function 

The current position of the roller sun blind is stored in the panoramic sliding sunroof control unit by the position recognition. The memory position is stored each time the manual adjustment is terminated (after t = 0.5 s), if the position is in the permissible range between roller sun blind closed position and roller sun blind open position. When the roller sun blind is opened automatically, the last set and stored roller sun blind position is actuated. If the rear roller sun blind is located in this position, if it opened to the end position.

IMPORTANT The memory function is activated via the diagnosis tester.

Function sequence for panoramic sliding sunroof memory function 

The current position of the panoramic sliding sunroof is stored in the panoramic sliding sunroof control unit by the position recognition. The memory position is stored each time the manual adjustment is terminated (after t = 0.5 s), if the position is in the permissible range between pop-up roof open position and anti-wind-hum position. When the panoramic sliding roof is opened automatically, the last set and stored roller sun blind position is actuated.

If the panoramic sliding roof is located in this position, if it opened to the end position. If this set panoramic sliding roof position is changed by manual adjustment, the old memory position is overwritten by the current position.

IMPORTANT The memory function is activated via the diagnosis tester.

  Electrical function schematic for panoramic sliding sunroof   PE77.20-P-2052-97FBA 
  Overview of system components, panoramic sliding sunroof   GF77.20-P-9991RF 
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