Electric Panoramic Sliding Sunroof, Function - GF77.20-P-0003RF

Model 205, 253 

with code 413 (Automatic panoramic sliding sunroof) 

Courtesy of MERCEDES-BENZ USA

Model 205, 253 (except code 830 (additional parts for China vehicles)) 

Courtesy of MERCEDES-BENZ USA

Model 205.1 as of model year 2019 with code 830 (additional parts for China vehicles), 253.1 as of model year 2020 with code 830 (additional parts for China vehicles) 

Function requirements, general 

• No overvoltage or undervoltage
• Transport mode not activated

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. An extended roller sunblind is retracted before the panoramic sliding sunroof is opened. The panoramic sliding sunroof is operated via the roof system switch at the overhead control panel control unit.

Overheating protection: 

The panoramic sliding sunroof motor and the roller sunblind motor are protected against overheating by a software thermal protection in the panoramic sliding sunroof control unit. The temperature in the panoramic sliding sunroof motor and roller sunblind motor is calculated taking into account the voltage, current and actuation duration as well as the 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.

Recognition of switch signals: 

The actuation of the roof system switch is clearly detected after 40± 10 ms. The max. actuation duration is 20 s. A defective roof system switch is interpreted after 60 s. 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.

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.

Roof rack 

If a roof rack is installed on the vehicle, the panoramic sliding sunroof should not be opened. A roof rack approved by Mercedes-Benz has an end stop. This prevents damage when the panoramic sliding sunroof is opened. Once the panoramic sliding sunroof comes into contact with this end stop, the panoramic sliding sunroof control unit detects an obstacle due to the changed power consumption of the panoramic sliding sunroof motor. Actuation is interrupted and reversing is started up to the tilt position.

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

• Position detection 
• Normalize panoramic sliding roof 
• Blockage detection 
• Automatic reserving function 
• Open/close roller sun blind 
• Open/close panoramic sliding roof 
• Rain closing (except code 494 (USA version)) 
• Speed-dependent tilt adjustment 
• Memory function 

Position detection 

The position of the panoramic sliding sunroof and that of the roller sunblind are determined by the panoramic sliding sunroof control unit by evaluating the signals of the following sensors:

• Hall sensor 1, panoramic sliding roof
• Hall sensor 2, panoramic sliding roof
• Hall sensor 1, panoramic sliding sunroof roller sunblind
• Hall sensor 2, panoramic sliding roof roller sun blind

The Hall sensors are located on the shafts of the roller sunblind motor and panoramic sliding sunroof motor, offset in each case by 90°. The position of the panoramic sliding sunroof and roller sunblind are detected by counting the Hall sensor pulses. The zero position (roller sunblind and/or panoramic sliding sunroof fully closed) is set via normalization.

If the Hall sensors fail, the roller sunblind can only be actuated incrementally at intervals of, in each case, 0.3 s. The panoramic sliding roof can only be closed with the hand crank.

Additional function requirements for "Normalize panoramic sliding sunroof" 

• Roller sun blind and/or panoramic sliding sunroof denormalized
• Roller sunblind and/or panoramic sliding sunroof open (minimum distance to zero position)

Normalize panoramic sliding roof 

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 sunblind must be closed completely.

Close the panoramic sliding sunroof and/or roller sunblind using the roof system switch until the mechanical end position is reached. Then reactuate roof system switch for min. 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:

• With circuit 30 OFF while actuating roller sun blind motor or panoramic sliding roof motor
• If the panoramic sliding sunroof exceeds the defined movement range by 25 motor rotations
• If the defined Hall sensor signal sequence is faulty
• If the positions of the roller sun blind and panoramic sliding sunroof are implausible relative to each other

The position of the panoramic sliding sunroof and the roller sunblind cannot be determined in the denormalized state. The function is then limited to manual closing or opening. Actuation is possible only in steps of 0.5 s each.

Blockage detection 

An obstruction is detected, if no Hall sensor signals are detected during an adjustment for approx. 160 ms.

If an obstruction is detected in the closing direction, the roller sunblind motor and panoramic sliding sunroof motor are first stopped and then actuated in the opposite direction. If an obstruction is detected in the opening direction, the roller sunblind motor and panoramic sliding sunroof motor are stopped and not further actuated.

Additional function requirements for automatic reversing function 

• Roller sunblind and/or panoramic sliding sunroof normalized
• Valid reference data present for automatic reversing function

Automatic reserving function 

If the closing of the panoramic sliding sunroof or roller sunblind is obstructed or restricted, the panoramic sliding sunroof or roller sunblind automatically opens again.

The automatic reversing function is based on the comparison of the current rotational speed of the roller sunblind motor or panoramic sliding sunroof motor with that determined during a teach-in run or due to an adaptation.

If a specific limit value is exceeded during closing during this comparison, the panoramic sliding sunroof control unit evaluates this as an obstruction.

During automatic opening, the automatic reversing function is active in a limited range (protection against risk of blockage from glass cover rear edge/roof rack or roof railing).

During a teach-in run, the roller sunblind and the panoramic sliding sunroof are moved in normalized status through all closing processes. The panoramic sliding sunroof control module adapts to changes in the RPM resulting from increased sluggishness (e.g. dirt in the mechanical system).

Where an obstacle is detected during opening, the roller sunblind motor and panoramic sliding sunroof motor are solely stopped. Where an obstacle is detected during closing, the roller sunblind motor and panoramic sliding sunroof motor are initially stopped and then reversed (in the opposite direction).

Reversing of 145 mm is performed during automatic closing. Reversing of 70 mm is performed with the rain closing function. Reversing of 20 mm is performed during manual closing.

Special case closing panoramic sliding sunroof manually: 

A higher force expenditure is permitted where the roof system switch is actuated in the close direction within 2 s of reversing. The next closing attempt deactivates the automatic reversing function.

additional function requirements for opening/closing of roller sun blinds 

• Panoramic sliding roof closed
• Roller sun blind normalized
• Valid reference data present for automatic reversing function
• Circuit 15R ON or run-on time active (up to t = 5 min after circuit 15R OFF, with front doors not yet open)

The electronic ignition lock control unit sends the status of circuit 15 to the panoramic sliding sunroof control unit via the interior CAN.

When a front door is opened or closed during the run-on time, this triggers a restart of the run-on time. The front door control units transmits the status of the front doors (open or closed) to the panoramic sliding sunroof control unit via interior CAN.

Open/close roller sun blind 

The roller sunblind is opened or closed for the actuation duration via the actuation of the roof system switch to the first detent. The roller sunblind is moved to the last saved position or fully opened or closed via the actuation of the roof system switch beyond the first detent. The automatic operation is canceled by actuating the roof system switch again.

The overhead control panel control unit directly reads in the status of the roof system switch. In vehicles up to model year 2019, the overhead control panel control unit transmits the status via the roof LIN, front SAM control unit and interior CAN to the panoramic sliding sunroof control unit. In vehicles from model year 2019, the overhead control panel control unit transmits the status via the interior CAN to the panoramic sliding sunroof control unit. The panoramic sliding sunroof control unit accordingly actuates the roller sunblind motor. The automatic reversing function is active during closing.

For model 205.1 as of model year 2019 with code 830 (additional parts for China vehicles) and model 253.1 as of model year 2020 with code 830 (additional parts for China vehicles), the roller sunblind can additionally be actuated from the rear seat. The push button switch is located in the rear, in the center console.

Additional function requirements for opening/closing panoramic sliding sunroof 

• Roller sun blind OPEN
• Panoramic sliding sunroof normalized
• Valid reference data present for automatic reversing function

• Circuit 15R ON or run-on time active (up to t = 5 min after circuit 15R OFF, with front doors not yet open)

The electronic ignition lock control unit sends the status of circuit 15 to the panoramic sliding sunroof control unit via the interior CAN.

When a front door is opened or closed during the run-on time, this triggers a restart of the run-on time. The front door control units transmits the status of the front doors (open or closed) to the panoramic sliding sunroof control unit via interior CAN.

Open/close panoramic sliding roof 

The panoramic sliding roof function comprises the following partial functions:

• Open/close panoramic sliding sunroof in slide position 
• Raise/lower panoramic sliding sunroof in tilt position Open/close panoramic sliding sunroof in slide position 

The panoramic sliding sunroof is opened or closed for the actuation duration via the actuation of the roof system switch to the first detent. The panoramic sliding sunroof is moved to the last saved position or fully opened or closed via the actuation of the roof system switch beyond the first detent. Automatic operation is canceled by actuating the panoramic sliding sunroof switch again.

The overhead control panel control unit directly reads in the status of the roof system switch. In vehicles up to model year 2019, the overhead control panel control unit transmits the status via the roof LIN, front SAM control unit and interior CAN to the panoramic sliding sunroof control unit. In vehicles from model year 2019, the overhead control panel control unit transmits the status via the interior CAN to the panoramic sliding sunroof control unit. The panoramic sliding roof control unit actuates the panoramic sliding roof motor. The automatic reversing function is active during closing. During automatic opening, the automatic reversing function is active in a limited range (protection against risk of blockage from glass cover rear edge/roof rack or roof railing).

Additional function requirements for raising/lowering panoramic sliding sunroof in tilt position 

• Panoramic sliding sunroof completely closed

Raise/lower panoramic sliding sunroof in tilt position 

The panoramic sliding sunroof is raised in the tilt position or lowered out of this for the actuation duration via the actuation of the roof system switch to the first detent. An automatic operation starts where the roof system switch is actuated beyond the first detent. The panoramic sliding sunroof is raised to the last saved position or fully raised in the tilt position or lowered from this. Automatic operation is canceled by actuating the panoramic sliding sunroof switch again.

The overhead control panel control unit directly reads in the status of the roof system switch. In vehicles up to model year 2019, the overhead control panel control unit transmits the status via the roof LIN, front SAM control unit and interior CAN to the panoramic sliding sunroof control unit. In vehicles from model year 2019, the overhead control panel control unit transmits the status via the interior CAN to the panoramic sliding sunroof control unit. The panoramic sliding roof control unit actuates the panoramic sliding roof motor. The automatic reversing function is active during closing.

Rain closing (except code 494 (USA version)) 

The automatic rain closing function prevents rainwater from entering into the vehicle interior. A panoramic sliding sunroof opened in the slide position is fully closed and raised in the tilt position. A panoramic sliding sunroof fully opened in the tilt position is lowered in the case of heavy rain.

Rain closing comprises the following partial functions:

• Rain closing function when vehicle is parked 
• Dynamic rain closing function (during vehicle operation) 

  Additional function requirements for rain closing when vehicle is parked 

• Panoramic sliding sunroof opened in sliding position
• Panoramic sliding sunroof normalized
• Valid reference data present for automatic reversing function
• Circuit 15R OFF or vehicle locked

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

Rain closing function when vehicle is parked 

When it starts to rain, the panoramic sliding sunroof that is opened in the slide position is fully closed and raised into the tilt position. "Starting to rain" is defined via the wetness of the windshield.

Moistening the windshield is recognized by the rain/light sensor with additional functions. The rain/light sensor with additional functions reads in the signals from the rain sensor directly and evaluates them. It then transmits the "rain closing function" request via the rain and light sensor LIN, front SAM control unit and interior CAN to the panoramic sliding sunroof control unit. 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.

Model 205, 253

with code 413 (Automatic panoramic sliding sunroof)

with code 882 (Interior motion sensor)

To prevent an unintentional triggering of the anti-theft alarm system (ATA), an alarm triggering is suppressed by the interior protection during the rain closing function.

The rain closing function is also triggered under the following conditions:

• After 6 h
• In the case of faults in the power supply

  Additional function requirements for dynamic rain closing function (during vehicle operation) 

• Panoramic sliding sunroof fully raised in tilt position
• Panoramic sliding sunroof normalized
• Valid reference data present for automatic reversing function
• Vehicle speed above 0 km/h
• No activated operation request from the panoramic sliding sunroof

Dynamic rain closing function (during vehicle operation) 

With the dynamic rain closing function, the raised panoramic sliding sunroof automatically lowers out of the tilt position during vehicle operation in the case of heavy rain. In doing so, the rain intensity and vehicle speed are taken into account.

The activity of the windshield wiper system allows for conclusions on the rain intensity. The windshield wiper system is controlled by the front SAM control unit. In the case of high windshield wiper system activity, the front SAM control unit transmits the "Rain closing function" request via the interior CAN to the panoramic sliding sunroof control unit. 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 sunroof control unit evaluates the data and accordingly actuates the panoramic sliding sunroof motor.

The dynamic rain closing function can be interrupted by momentarily actuating the roof system switch, and the panoramic sliding roof can be adjusted to any position.

Additional function requirements for speed-dependent tilt adjustment 

• Panoramic sliding sunroof fully opened in tilt position
• Panoramic sliding sunroof normalized
• Valid reference data present for automatic reversing function
• Vehicle speed above 0 km/h
• No activated operation request from the panoramic sliding sunroof

Speed-dependent tilt adjustment 

If the panoramic sliding sunroof is fully opened in the tilt position, it automatically lowers at higher speeds. Depending on the driven speed, the panoramic sliding sunroof is lowered in two stages. The wind noises in the vehicle interior are thus reduced. When a defined speed threshold is undershot, the panoramic sliding sunroof automatically raises again into the tilt position.

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 sunroof control unit then accordingly actuates the panoramic sliding sunroof motor.

Additional function requirements for the memory function 

• Roller sunblind and/or panoramic sliding sunroof normalized
• Valid reference data present for automatic reversing function

Memory function 

At the end of a manual adjustment, the positions of the roller sunblind and panoramic sliding sunroof are saved in the panoramic sliding sunroof control unit.

During the automatic opening of the roller sunblind and/or panoramic sliding sunroof, the last saved positions are moved to.