GF72.29-P-0003LA Power Windows (PW (EFH)), Function

GF72.29-P-0003LA Power Windows (PW [EFH]), Function
- as of model year 09

Function requirements, general
^ C. 15R On
^ No overvoltage or undervoltage
^ Run-on time active (up to t = 5 min. after circuit 15R Off, if front doors are not yet open)

The circuit status is transmitted by the EIS control unit (N73) to the interior CAN. The status of the front door is recognized by the left door lock unit (A85) or right door lock unit (A85/1), read in by the left door control unit (N69/1) or right door control unit (N69/2) and transmitted to the interior CAN.

Power windows (PW), general
The side windows in the front door and the rear side windows can be opened and closed with the power window lifter.

The convenience feature is a possibility to open and close the side windows from one central control point. The convenience features are described in the separate convenience feature (CF) function.

The following switches are integrated in the driver power window outside mirror and trunk lid switch group (S20/1):
- Left front power window switch (S20/1s1)
- Right front power window switch (S20/1s2)
- Left rear power window switch (S20/1s3)
- Right rear power window switch (S20/1s4)
- Rear side window child safety lock (S20/1s5)

The side windows can be opened and closed from the driver position with these switches.
Operation of the left rear power window switch (S21/3) and right rear power window switch (S21/4) can be inhibited with the rear side window child safety lock switch. Only the corresponding side window can be opened and close with the passenger pow window switch (S21/2), left rear power window switch and right rear power window switch.

Depending on priority, active adjustments can be aborted by the other control points.

The power window system comprises the following partial functions:
^ Function sequence for manual raising and lowering
^ Function sequence for automatic raising and lowering
^ Function sequence for child safety lock
^ Function sequence for position recognition
^ Function sequence for normalization
^ Function sequence for denormalization
^ Function sequence for anti-pinch protection
^ Function sequence for short stroke
^ Function sequence for short stroke in limp-home mode
^ Function sequence for thermal protection
^ Priority function sequence

Additional function requirements for manual raising and lowering
^ Power windows normalized
^ Child safety lock switched off (only for rear window)

Function sequence for manual raising and lowering
Actuate and hold down corresponding power window switch to the first catch point or beyond in the opening or closing direction.

The positions of the power window switch in the driver-side switch group is read in by the left front door control unit via left door LIN. The switch position of the passenger power window switch can be read in directly by the right door control unit.

The switch position of the left rear power window switch and right rear power window switch are read in directly by the rear control unit (N22/6).
The left door control unit then actuates the left rear power window motor (M10/3), the right door control unit actuates the right front power window motor (M10/4).
The rear control units actuates the left rear power window motor (M10/5) or right rear power window motor (M10/6).

Actuation (max. t = 5 s) takes places for as long as the corresponding request is maintained or until the side window reaches the lower or upper stop.

The duration of the actuation for the power window motors is limited to t = 25 s. New actuation is only possible after recognizing the rest position.

Additional function requirements for automatic raising and lowering
^ Power windows normalized

Function sequence for automatic raising and lowering
Actuate corresponding power window switch momentarily beyond the first catch point in the opening and closing direction.
The remaining function sequence corresponds to that of manual raising and lowering. The anti-pinch protection function is always active during automatic raising.

Only automatic lowering is possible for the rear side windows, raising is accomplished manually.

Function sequence for child safety lock
When the child safety lock (rear side window child safety lock actuated), the control of the rear side window and is inhibited via the rear side window switch.
Actuations already activated are interrupted immediately.
The status of the rear side window child safety lock switch is read by the left front door control unit via the front door LIN and transmitted to the rear SAM control unit via the interior CAN. If the child safety lock function is activated, the LED in the rear side window child safety lock switch is on.

If the position of the rear side window child safety lock switch can no longer be read with certainty, the child safety lock function is regarded as permanently switched on.

Function sequence for position recognition
The location counter in the door control unit in question or in the rear control unit evaluates the signals from the Hall sensors on the power window motors.
The zero position is the upper stop (window fully closed) and is set by the normalization procedure. Depending on the actuation direction, the counter is increased when "opening" and correspondingly decreased when "closing" the windows.

Normalization function sequence
Normalization means teaching in the upper mechanical window stop (zero point) to the corresponding door control unit and rear control unit.
For this purpose completely close corresponding side window with the manual raising function. After releasing the power window switch, the side window lowers approx.approx. s = 20 mm. The power window switch must be actuated again within t = 4 s and the switch must be actuated for another t > 300 + 50 ms upon reaching the upper end position of the side window. The location counter in the responsible door control unit is then set to z = 0.

Function sequence for denormalization
The power windows are denormalized under the following circumstances:
- A door control unit or the rear control unit recognizes a location counter status greater than the maximum adjustment range.
- A door control unit or the rear control unit recognizes a location counter status exceeding the zero point tolerance for the stored zero point.
- A door control unit or the rear control unit recognizes faulty Hall sensor signals or no Hall sensor signals or incorrect direction of rotation when actuating the power window motor.
- The supply voltage (c. 30) in the corresponding control unit remains off for t > 30 s.

The cause for the normalization is stored in the corresponding door control unit or in the rear control unit. When the power windows are denormalized, only the manual raising and lowering functions are possible.

Additional function requirements for anti-pinch protection
^ Power windows normalized

Function sequence for anti-pinch protection
If the force does not increase or the Hall sensor signals do not change when raising the side window of the door control unit or rear control unit, this is evaluated as pinching. Raising is immediately stopped and the side opens automatically..

The anti-pinch protection function is actuated depending on the type of raising (automatic/manual).

The ant-pinch protection function comprises the following partial functions:
^ Function sequence for anti-pinch protection after manual actuation
^ Function sequence for anti-pinch protection after automatic actuation

Additional function requirements for anti-pinch protection after manual actuation
^ Side window open s = 3 mm to s = 230 mm

Function sequence for anti-pinch protection after manual actuation
Anti-pinch protection is active during manual raising in three stages of different intensity.
If a door control unit or the rear control unit recognizes pinching (overload), actuation is interrupted and the side window is opened when the power window switch is released for a maximum of s 125 mm (programmable). If a new request is present within t = 2 s, the response time of the excess force limiter is increased. If pinching is recognized again, the actuation is interrupted again and side window opened s = 20 mm. If a new request is present from t = 5 s to t = 10 s after the 2nd stop, the window is closed without the excess force limiter.

Function sequence for anti-pinch protection after automatic actuation
If a door control unit recognizes pinching, actuation is interrupted and the side window is opened immediately. When a new request is present within t = 2 s, the operation is again interrupted and the window is then opened. If a new request is present within t = 2 s after the second request, actuation is interrupted and only manual closing is possible.

The excess force limiter is activated even when power windows are not normalized upon reaching the upper lock position. This leads to reversing.
When actuated a second time within t = 2 s the excess force limiter is switched off. This allows normalization at the upper stop.

Additional function requirements for short stroke
^ Power windows normalized
^ Valid Hall sensor signals present

Function for short stroke opening/closing
When the driver or passenger door is opened, the associated front and rear side window is lowered to the short stroke position. This allows the doors and the frameless side windows to be opened without obstructions
As long as the short stroke is activated, the corresponding side window cannot be moved beyond the short stroke position closed with the left front power window, right front power window switch or passenger power window switch.
The short stroke position is at s = 4 mm to 1 mm inside width, measured between the bottom edge of the outer sealing lip and the top edge of the window. The window is lowered without time delay after the signal "Door open" is recognized.

The side windows remain in this position until the signal "Door closed" is recognized or the power window switch is actuated.

Closing with the short stroke function is not possible on non-normalized power windows.

If the signal "Door open" changes to "Door closed" and if the signal "Door closed" as well as "Short stroke not active" are present, the side window is closed to the zero position. If the corresponding side window is outside the short stroke area, short stroke is not accomplished.
All parameters for the short stroke function are stored in the corresponding door control unit and rear control unit. Two different counter statuses are required for the short stroke function of the side windows: Short stroke position 1 for actuating the short stroke function from the top and short stroke position 2 for the position when closing the side window. These differences compensate the mechanical play of the power windows.

Additional function requirements for short stroke limp-home mode
^ Power window not normalized or
^ no Hall sensor signals present

Function sequence for short stroke in limp-home mode
After recognizing "Door open" or actuating the front power window switch in the "Open" direction, the corresponding rear side window is lowered to the short stroke travel without time delay as described for the short stroke opening/closing function.
Short stroke closing is not possible in the limp-home mode. Completely closing the side windows in the lock position is only possible manually. If, in this case, the driver and rear windows are normalized, the side window in question is lowered to the short stroke position.
If the power windows are normalized and the "Short stroke open" function activated and the Hall sensor inputs do not change for t = 150 ms + 20 ms, actuation is canceled.

The short stroke opening function is reactivated after t = 4 s. If adjusted to the opening direction the corresponding short stroke position is moved to and the short stroke function is continued according to the function conditions.

This is intended to prevent failure of the short stroke function by actuation of the temperature switch in the power window motor. If the Hall sensor inputs do not change following the 2nd actuation the short stroke function is interrupted. If the short stroke opening function is requested again the opening function is actuated. In this case closing is not performed by the short stroke function.

Function sequence for thermal protection
The power window motors are protected by a software-based thermal protection function in the respective door control unit or rear control unit. The temperature of the power window motor bearings is calculated according to the voltage, power, actuation duration and outside and inside temperature. After reaching a certain threshold value, the corresponding power window motor is actuated only until the request is no longer present or the end stop is reached.

It is possible to reactuate the corresponding power window motor after a cooling phase calculated by the door control unit or rear door control unit.

Priority function sequence
1. Alarm closing
2. Short stroke open/close
3. Driver-side control point
4. Passenger control point or control points in rear
5. Actuation for handicapped vehicle (special equipment)
6. Close windows via PRE-SAFE
7. Open window with crash ventilation
8. Actuation with diagnosis
9. Central opening/closing via Keyless-Go (with code (889) Keyless Go)
10. Central opening/closing via transmitter key (A8/1)
11. Convenience opening/closing via recirculated air function
12. Short stroke closing

A request with higher priority is performed if a power window function with lower priority is currently active. The function with lower priority is interrupted first and with the second valid actuation the corresponding function starts.
If a command with lower priority is still present after completion of an operation request with higher priority, the former command is ignored.

It is first necessary for the controls to recognize non-actuation of the lower priority command before the corresponding function can be activated.

A command with lower priority cannot affect an active power window function of higher priority.