Sliding Roof, Function - GF77.20-P-0008GWM
Model 463 (except 463.342) as of model year 2019 with code F15 (Sliding sunroof)
Function requirements, general
- No overvoltage or undervoltage
- Consumer shutoff not active
- Transport mode not activated
Sliding roof, general
Operation occurs by means of the roof system switch in the overhead control panel control unit. The sliding roof is a combined sliding/tilting roof. The sliding roof function lowers the sliding door toward the rear into the headliner. The electric tilting roof function lifts the rear section of the sliding roof.
The sliding roof can also be operated using the convenience features, which allow the sliding roof to be opened and closed centrally together with the side windows from one control point.
Overheating protection:
An integrated thermal protection switch protects the sliding roof motor against overload.
The sliding roof motor is switched off if the maximum permissible operating time is exceeded.
If the overheating protection function was triggered, actuation is disabled for the 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:
- Function sequence for normalization
- Function sequence for position monitoring and blockage detection
- Function sequence for opening/closing sliding roof
- Function sequence for automatic reserving function
- Function sequence for rain closing
Additional function requirements for normalizing
- Sliding roof denormalized
- Circuit 15R ON or run-on time active (up to t = 5 min after circuit 15ROFF, with closed front doors)
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.
Function sequence for normalization
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 completely opened. Completely open sliding roof using roof system switch 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 press the roof system switch again for at least t = 1 s. The sliding roof control module recognizes blockage by evaluating the signals from sliding roof Hall sensor 1 and sliding roof Hall sensor 2 and sets the corresponding 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:
- With circuit 30 OFF during actuation of sliding roof motor
- If the sliding sunroof exceeds the defined movement range
- If one of two Hall sensors fails for 10 signal edges
- If both Hall sensors fail to supply signals for longer than t = 320 ms when reversing
- With sliding roof actuation when voltage is too low
The position of the sliding roof cannot be determined in the denormalized condition. The function is then restricted to manual closing or opening in increments of t = 0.5 s each.
Additional function requirements for position monitoring and blockage detection
- Active actuation of sliding roof
Function sequence for position monitoring and blockage detection
The sliding roof control module monitors the position of the sliding roof by evaluating the signals from the following sensors:
- Hall sensor 1, sliding roof
- Hall sensor 2, sliding roof
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 in tilt position" is defined as zero position. The zero position is set by normalization. Blockage is detected if no signals from the Hall sensors are detected for a period of t = 350 ms during adjustment. 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 t = 5 min after circuit 15R OFF, when front doors are not yet open) present.
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.
No request via PRE-SAFE®. Requests transmitted via PRE-SAFE® take priority and result in the termination of a manual or automatic opening or closing process.
The PRE-SAFE® function of the sliding sunroof is described elsewhere.
Function sequence for opening/closing sliding roof
The sliding roof can be opened and closed manually or automatically.
The sliding roof is opened or closed manually for the time the request is active by actuating the roof system switch to the first catch.
The sliding roof is fully opened or closed automatically by actuating the roof system switch beyond the first catch.
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.
If the sliding sunroof is denormalized, it can be actuated only manually and in increments of t = 0.5 s each.
Recognition of witch signals:
Actuation of the roof system switch is clearly recognized only after t = 40 + 10 ms. The maximum activation time is t ≥ 20 s. After t ≥ 60 s, the system considers the roof system switch to be "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.
Additional function requirements for automatic reversing function
- Sliding roof NORMALIZED
- Valid reference data present for automatic reversing function
Function sequence for 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 this difference exceeds a certain limit value during a closing operation, this is detected as a pinching of the overhead control panel control unit.
Teach-in run:
During a learn-in run all of the sliding roof closing procedures are accomplished in the normalized condition. The sliding roof control module adapts a change in the power consumption of the sliding roof motor resulting from increased sluggishness (e.g. dirt in the mechanical system).
If a blockage 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 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 rain closing
- Circuit 15R OFF or vehicle locked
- 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.
Function sequence for 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 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 sliding roof control module. 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.
Rain closing is performed even if the run-on time (t = 6 h) has expired or the voltage or temperature is no longer within the range of the rain sensor.
During rain closing, an alarm actuation is suppressed by the interior protection to prevent an unintentional actuation of the anti-theft alarm system (ATA).
| Electrical function schematic for sliding roof | PE77.20-P-2054-97ZGB | |
| Overview of system components of sliding roof | GF77.20-P-9996GWM |