Electric Power Sliding Roof, Function - GF77.20-P-0007FR
Model 257, 290
up to model year 2021
with code 414 (Electric sunroof, glass version)
Function requirements, general
- No overvoltage or undervoltage
- Consumer shutoff not active
- Transport mode not activated
Sliding roof, general
The sliding sunroof has a combined tilting/sliding roof design. The sliding sunroof function lowers the sliding sunroof toward the rear under the roof lining. The tilting roof function lifts the rear section of the sliding sunroof. Operation occurs by means of the roof system switch in the overhead control panel control unit.
The sliding sunroof can also be opened or closed via the convenience functions. These allow for a central opening or closing of the sliding sunroof together with the side windows from one control point.
Overheating protection:
The sliding sunroof motor is protected from overheating by an integrated thermal protection switch. If a specific operating time is exceeded, the sliding sunroof motor is switched off. If the overheating protection was triggered, the actuation of the sliding sunroof motor is disabled for a minimum cooling time. The overheating protection function does not operate during roof reversal (after a blockage is detected).
The sliding roof function comprises the following partial functions:
- Normalizing
- Position monitoring and blockage detection
- Open/close sliding roof
- Automatic reserving function
- Rain closing
Additional function requirements for normalizing
- Sliding roof denormalized
- Circuit 15R ON or run-on time active (up to 5 min after circuit 15R OFF and front doors closed)
The electronic ignition lock control unit sends the status of circuit 15 via interior CAN to the sliding roof control module.
The front door control units transmit the status of the front doors (open or closed) to the sliding sunroof control module via interior CAN.
Normalizing
Normalizing is the basis for assigning the current position to the position of the sliding roof sensed by the sliding roof control module. For this purpose, the sliding roof must be closed completely and lifted into the tilt position.
Completely close the sliding roof via the roof system switch and lift into the tilt position until the mechanical end stop is reached. The overhead control unit transmits the status of the roof system switch to the sliding roof control module via the interior CAN. Then reactuate roof system switch for min. 1 s. The sliding roof control module recognizes an obstruction by evaluating the signals of the Hall sensors and sets the location counter to zero.
When normalized, the sliding roof system motor is switched off by the sliding roof module before the mechanical stop is reached during automatic opening and closing.
Denormalization is performed under the following conditions:
- In the event of voltage breakdown during actuation of the sliding sunroof motor
- If the sliding roof exceeds the defined movement range
- If one of the two Hall sensors fails for 10 signal edges
- If both Hall sensors fail to supply signals for longer than 320 ms when reversing
- For actuation of the sliding sunroof motor in the event of undervoltage
The position of the sliding roof cannot be determined in the denormalized condition. The function is then restricted to manual closing and opening in increments of 0.5 s each.
Additional function requirements for position monitoring and blockage detection
- Active actuation of the sliding sunroof motor
Position monitoring and blockage detection
The sliding roof control module monitors the position of the sliding roof by evaluating the Hall sensor signals.
The Hall sensors are arranged offset by 90° on the axis of the sliding roof motor. The position of the sliding roof is determined by counting the Hall sensor pulses. The position "sliding roof open in tilt position" is defined as zero position. The zero position is set by normalization. An obstruction is detected if, during an adjustment for approx. 350 ms, no signals of the Hall sensors are recognized. If the blockage is recognized in the closing direction, the sliding roof motor is first stopped and then actuated in the opposite direction. If the blockage is recognized in the opening direction, the sliding roof motor is stopped and no longer actuated.
Additional function requirements for opening/closing sliding roof
- Circuit 15R ON or run-on time active (up to 5 min after circuit 15R OFF and front doors closed)
The electronic ignition lock control unit sends the status of circuit 15 via interior CAN to the sliding roof control module.
The front door control units transmit the status of the front doors (open or closed) to the sliding sunroof control module via interior CAN.
Open/close sliding roof
The sliding roof can be opened and closed manually or automatically. By actuating the sliding roof system switch up to a noticeable resistance, the sliding sunroof is manually opened or closed for the duration of the adjacent request.
By actuating the sliding roof system switch from this roof system resistance, the sliding sunroof is automatically completely opened completely closed.
Automatic adjustment is aborted if the roof system switch is actuated again. The automatic reversing function is active during closing. The overhead control unit transmits the status of the roof system switch to the sliding roof control module via the interior CAN. The sliding roof control module actuates the sliding roof motor according to the selected actuation direction for the time the request is present.
When the sliding sunroof is denormalized, it can only be actuated in steps of 0.5 s each.
Recognition of switch signals:
The actuation of the roof system switch is clearly recognized after 40 (± 10) ms. The max. actuation time is 20 s. After 60 s, a defective roof system switch is detected. A new actuation (triggered via the roof system switch) can be performed again only after detecting that the roof system switch is in the rest position.
Additional function requirements for automatic reversing function
- Sliding roof NORMALIZED
- Valid reference data present for automatic reversing function
Automatic reserving function
The automatic reversing function is based on a comparison between the current power consumption of the sliding roof motor and the power consumption recorded during a teach-in run or adaptation. If the difference between the values exceeds a specific limit value during a closing process, this is detected by the sliding sunroof control module as an obstruction.
Teach-in run:
During a learn-in run all of the sliding roof closing procedures are accomplished in the normalized condition. The sliding sunroof control module adapts a change in the power consumption of the sliding sunroof motor resulting from increased sluggishness (e.g. dirt in the mechanical system).
If an entrapment is detected during an opening procedure, the sliding roof is stopped. During a closing procedure, the sliding roof is stopped and then reversed (moved in the opposite direction).
Special case, manual closing:
If the roof system switch is actuated again in the closing direction within 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 rain closing
- Circuit 15R OFF or vehicle locked via the central locking system
- Sliding roof open in slide position
- Sliding roof NORMALIZED
The circuit 15 status and the central locking status are sent by the electronic ignition lock control unit over the interior CAN to the sliding roof control module.
Rain closing
The 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 from the rain sensor directly and evaluates them. The rain and light sensor with additional functions then transmits the request for the "rain closing function" to the sliding sunroof control module via the rain and light sensor LIN, front SAM control unit and interior CAN. The sliding roof control module then actuates the sliding roof motor. The sliding roof is moved to the tilt position. Monitoring is then no longer performed.
The rain closing function is carried out under the following conditions:
- When it starts to rain
- In extreme outside temperatures
- After 6 hours
- In the case of faults in the power supply
Model 257, 290
up to model year 2021
with code 414 (Electric sunroof, glass version)
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.
| Electrical function schematic for sliding roof | PE77.20-P-2054-97XBA | ||
| Overview of system components for electric power sliding roof | GF77.20-P-9989FR |