Electric tilting/sliding roof (SR), function - GF77.20-P-0001CE
MODEL 204.0/2 with CODE (414) Power glass tilting/sliding roof as of model year 2009/YoM 08
Function requirements, general
- C. 30 ON
- No overvoltage or undervoltage
Electric tilting/sliding roof (SHD), general
The electric tilting/sliding roof (SHD) function allows the tilting/sliding roof to be opened and closed.
Operation is accomplished via the tilting/sliding roof switch (N70s1) in the overhead control panel control unit (N70).
The SHD is a combined tilting and sliding roof. The sliding roof function drops the SHD down and moves it backwards into the headliner, the tilting roof function raises the SHD at the rear.
There are convenience features allowing the SHD to be opened and closed from one central control point.
The convenience features are described in the "Convenience feature" (CF) function description.
Actuation possibility for tilting/sliding roof switch
The electric tilting/sliding roof (SR) function comprises the following subfunctions:
- Function sequence for SHD opening/closing
- Function sequence for rain closing (with code (345) Rain sensor without code (494) USA version)
- Function sequence for anti-pinch protection
- Function sequence for position monitoring and blockage detection
- Function sequence for normalization
- Function sequence for denormalization
- Function sequence for thermal protection
Additional function requirements for SHD opening/closing
- Circuit 15R ON or
- Run-on time active
(up to t = 5 min. after circuit 15R Off, if front doors are not yet open)
The circuit status c. 15R is sent by the electronic ignition lock control unit (N73) over the interior CAN (CAN B) to the overhead control panel control unit.
The status of the left front door lock (A85) is read in by the left front door control unit (N69/1), the status of the right front door lock (A85/1) is read in by the right front door control unit (N69/2) and sent to the overhead control panel control unit via the interior CAN.
Function sequence for SHD opening/closing
The electric SHD function comprises the following partial functions:
D Function sequence for manual SHD opening/closing
D Automatic opening/closing function sequence for SHD (not applicable for code (494) USA version as of 1.9.08)
Function sequence for manual SHD opening/closing
Actuation of the tilting/sliding roof switch to the first catch position is read in by the overhead control panel control unit. It then actuates the tilting/sliding roof motor (M12m1) in the tilting/sliding roof drive unit (M12) according to the desired actuation direction as long as the request is present.
When the SR is denormalized, it can only be actuated in steps of t = 0.5 s.
Function sequence for automatic SHD opening/closing
When the tilting/sliding roof switch is actuated momentarily beyond the first catch position, the SR is adjusted automatically according to the actuation direction to the corresponding end position. Automatic adjustment is interrupted when the tilting/sliding roof switch is actuated again.
Recognizing switch signals
Actuation is detected once the tilting/sliding roof switch is actuated without interruption for t = 40 ms ± 10 ms. The maximum activation time is t > 20 s.
After t > 60 s a "stuck" tilting/sliding roof switch is recognized. The function can only be performed again using the tilting/sliding roof switch once the rest position is detected again.
Additional function requirements for rain closing
- Circuit 15R OFF or vehicle locked
- SHD open in slide position
Function sequence for rain closing (with code (345) Rain sensor without code (494) USA version)
The rain closing feature is actuated if moisture is recognized on the windshield by the rain/light sensor (B38/2).
The front SAM control unit with fuse and relay module (N10/1) reads in the signal for the rain/light sensor via the wiper/inside rearview mirror (LIN 2) and transmits this to the overhead control panel control unit via the interior CAN. The overhead control panel control unit actuates the tilting/sliding roof motor, which adjust the SR to the tilt position. Monitoring is then no longer performed.
Rain closing is still accomplished when the run-on time (t = 6 h) has expired or the voltage or temperature is no longer within the voltage range (U = 10 V to 15 V) or temperature range (T = 5 °C to 85 °C) of the rain/light sensor.
Alarm triggering by interior protection (with code (882) Interior monitoring (only with ATA [EDW]) is suppressed during rain closing to prevent undesired triggering of the anti-theft alarm system (ATA [EDW]).
Additional function requirements for function sequence of anti-pinch protection
- Circuit 15R ON or
- Run-on time active
(up to t = 5 min. after circuit 15R Off, if front doors are not yet open)
Function sequence for anti-pinch protection
Anti-pinch protection operates by comparing the current power consumption of the tilting/sliding roof motor with the power consumption recorded during a teach-in run or adaptation.
If this comparison exceeds a certain limit value during a closing operation, this is detected as a blockage of the SHD by the overhead control panel control unit.
This involves operating all of the closing procedures of the SHD in the normalized condition. The overhead control panel control unit adapts to any change in power consumption of the tilting/sliding roof motor due to increased sluggishness (e.g. dirt in the mechanical components).
If a blockage is detected during an opening procedure, the SHD is simply stopped.
During a closing procedure, the SHD is stopped when pinching is recognized and then reversed (moved in the opposite direction).
Special case, manual closing:
If the sliding roof switch is again actuated in the closing direction within t = 2 s after reversing, greater force is applied. The anti-pinch protection function is deactivated for the next attempt.
Additional function requirements for position monitoring and blockage detection
- Circuit 15R ON or
- Run-on time active
(up to t = 5 min. after circuit 15R Off, if front doors are not yet open)
Function sequence for position monitoring and blockage detection
Position monitoring is performed by the overhead control panel control unit by evaluated in the signals from Hall sensor 1, tilting/sliding roof (M12b1) and Hall sensor 2, tilting/sliding roof (M12b2), which are positioned on the tilting/sliding roof motor axle offset at 90°.
The position of the SHD is determined and monitored by counting the Hall sensor pulses.
The zero position corresponds to the SHD position when tilted open. The zero position is set by normalization.
Blockage is detected if signals are no longer detected from the Hall sensors for a period of t = 350 ms.
Actuation of the tilting/sliding roof motor is interrupted in the event of blockage.
Additional function requirements for normalization
- Circuit 15R ON or
- Run-on time active
(up to t = 5 min. after circuit 15R Off, if front doors are not yet open)
Normalization function sequence
Manually open SR with tilting/sliding roof switch to tilt position and to rear sliding roof position until the mechanical stop is reached and continue to actuate tilting/sliding roof switch.
The signal must be present for at least t = 1 s so that the overhead control panel control unit detects blockage of the tilting/sliding roof motor and can set the location counter to zero.
When normalized, the tilting/sliding roof motor is switched off by the overhead control panel control unit before the mechanical stop is reached during automatic opening and closing.
Function sequence for denormalization
Denormalization takes place:
- If the tilting/sliding roof motor is actuated with c. 30 OFF.
- If the SHD exceeds the defined movement range
- If one of two Hall sensors fails for 10 signal edges.
- If both Hall sensor signals are missing for longer than t = 320 ms during roof reversal
- If an SHD actuation is started during undervoltage
The position of the SHD cannot be determined in the denormalized condition. 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 thermal protection
A thermal protection switch integrated into the tilting/sliding roof motor protects the tilting/sliding roof motor against overload. The tilting/sliding roof motor is not designed for continuous operation. If the maximum permissible operating time is exceeded, the tilting/sliding roof motor is switched off.
If the thermal protection function is triggered, actuation is disabled until the minimum cooling time has passed. The thermal protection function does not operate during roof reversal after a blockage is detected.
| Electrical function schematic for tilting/sliding roof (SHD) | PE77.20-P-2050-97FAB | |
| Overview of system components for tilting sliding roof (SR) | GF77.20-P-9994CE |