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

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

Function requirements, general
^ C. 15R ON or run-on time active (up to t = 5 min. after c. 15R is OFF, with doors not yet opened or not locked from outside)
^ No overvoltage or undervoltage

The circuit status is transmitted by the EIS control unit (N73) to the interior CAN. The status of the doors is detected by the left front door rotary tumbler microswitch (M14/6s1) and right front door rotary tumbler microswitch (M14/5s1), read by the rear SAM control unit (N10/8) and placed on the interior CAN.

Power windows (PW), general
The power windows function opens and closes the front and rear side windows as well as the left and right rear vent windows (model 164.8, 251 with Code (848) Electric side vent window).

The convenience functions allowing the side windows to be opened and closed centrally, are described in the separate function description "Convenience feature (CF").

The following control points are available:
- Power window and outside mirror adjustment switch group, driver (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 windows child safety lock switch (S20/1s5)
- Vent window switch (S20/1s17) (model 164.8, 251 with code (848) Electric side vent window)
- Front passenger power window switch (S21/2)
- Left rear power window switch (S21/3)
- Right rear power window switch (S21/4)

Priority sequence:
Depending on priority of the control point, active power window adjustments can be aborted by the other control points. A command 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.

The priority sequence is subdivided as follows::
1. Power window and outside mirror adjustment switch group, driver
2. Front passenger power window switch

Left rear power window switch

Right rear power window switch

3. Close side window with PRE-SAFE
4. Diagnosis - actuation
5. Convenience opening/closing via transmitter key (A8/1)
6. Comfort opening/closing via Keyless-Go (with code (889) Keyless Go)
7. Convenience opening/closing via recirculated air function

The power window (PW [EFH]) system comprises the following subfunctions:
^ Function sequence for manually raising and lowering side window
^ Function sequence for automatically raising and lowering side window
^ Function sequence for opening and closing rear vent window (model 164.8, 251 with code (848) Electric side vent window)
^ Function sequence for child safety lock
^ Function sequence position recognition of side window
^ Function sequence for normalizing side window
^ Function sequence for denormalizing side window
^ Function sequence for anti-pinch protection
^ Function sequence for side window power window motor thermal protection

Function sequence for manually raising and lowering side window
Actuate and hold down corresponding power window switch to the first catch point in the opening or closing direction.
The position of the power window switches in the driver-side power window and outside mirror adjustment switch group is read via the front door LIN by the left front door control unit (N69/1). The position of the passenger-side power window switch is read directly by the right front door control unit (N69/2).
The positions of the rear power window switches are read in by the front SAM control unit (N10).
The left front door control unit actuates the left front power window motor (M10/3). The right front door control unit actuates the right front power window motor (M10/4).
The left rear power window motor (M10/5) and right rear power window motor (M10/6) are actuated directly by the front SAM control unit.

The duration of actuation is limited to max. t = 25 s.
Actuation takes places for as long as the corresponding request is maintained or until the window reaches the lower or upper stop.

Additional function requirements for automatically raising and lowering side window
^ Power window normalized (only for automatic raising)
^ Function not blocked via variant coding

Function sequence for automatically raising and lowering side window
The corresponding power window switch must be actuated momentarily beyond the first catch point in the opening or closing direction and then released.
The corresponding power window motor is actuated until the side window is recognized to be fully open or fully closed. The remaining function sequence corresponds to that of manual raising and lowering.

The anti-pinch protection function is always active during automatic raising. If the power windows are not normalized, manual raising instead of automatic raising is performed.

Function sequence for opening and closing rear vent window
The rear vent windows can be opened or closed in pairs with the vent window switch integrated into driver side power window and outside mirror adjustment switch group.
The status of the vent window switch is read in by the left front door control unit via front door LIN and transmitted to the rear SAM control unit (N10/8) via the interior CAN.
This then actuates both the left vent window motor (M21/8) and the right vent window motor (M21/9) together. The vent windows are opened and closed automatically.

It is not necessary to normalize the rear vent windows simultaneously.

Function sequence for child safety lock
When the child safety lock is switched on with the rear side window child safety lock switch, the left rear power window an right rear power window switches are disabled. Actuations already activated are interrupted.

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 front SAM control unit via interior CAN.

The rear side window child safety lock switch is a switch which locks into position. This means that the child safety lock is active when the switch is locked in the lower position and deactivate when the switch is locked in the raised position

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 of side window
A Hall sensor is integrated into each power window motor for position and rotation direction recognition. The Hall sensor signals are evaluated in the corresponding door control unit as well as in the front SAM control unit by the location counter.
The counter reading increases in the direction "Open" and decreases in the direction "Close". The zero position is the upper stop (window fully closed) and is set by the normalization procedure.

Function sequence for normalizing side window
Normalization means teaching in the upper mechanical window stop (zero point) to the corresponding door control unit and front SAM control unit. It is necessary for automatic raising and blockage detection and for the software-simulated thermal protection function.

For this purpose, completely close the window in question with the manual raising function. When the window is closed, continue to hold switch for min. t = 0.5 s.
The location counter in the relevant door control unit or in the front SAM control unit is then set to z = 0.

Function sequence for denormalization
The power windows are denormalized under the following circumstances:
- The door control unit or the front SAM control unit detects a location counter reading which corresponds to a level greater than the maximum window travel.
- The door control unit or the front SAM control unit detects a location counter reading which exceeds the zero point tolerance for the stored zero point.
- The door control unit or the front SAM control unit detects no Hall sensor signals or faulty Hall sensor signals during actuation of the power window motor.
- No on-board power supply voltage (circuit 30 < 6.5 V) for t > 30 s.

Automatic raising is no longer possible after denormalization.

Function sequence for anti-pinch protection
The anti-pinch protection consists of the following subfunctions:
^ Function sequence for side window anti-pinch protection
^ Function sequence for vent window anti-pinch protection

Additional function requirements for side window anti-pinch protection
^ Power windows normalized
^ Side window s = 4 to 230 mm open

Function sequence for side window anti-pinch protection
If, during automatic window raising, the left front door control unit, right front door control unit or front SAM control unit recognize an increase in force or the Hall sensors remain unchanged, this is recognized as pinching.

Raising is immediately stopped and the window automatically opens s = 70 mm.
If automatic raising requested again within t = 5 s to t = 10 s, this is accomplished without the excess force limitation function. However, this applies only for the left front power window motor in the driver door.
When the window is raised, sluggish window operation is detected and used for preliminary control (adaptation) purposes when the window is actuated again
This adaptation is active during every window raising procedure.

Function sequence for vent window anti-pinch protection
Pinching is sensed by the left vent window obstruction sensor strip (B51/5) and right vent window obstruction sensor strip (B51/6).

The obstruction sensor strips are integrated into the window seals and are read in by the rear SAM control unit.
If pinching is recognized, the corresponding vent window reverses direction and is automatically and completely opened.

Function sequence for side window power window motor thermal protection
The power window motors are protected against overheating by a software-based thermal protection function in the respective door control unit or front SAM control unit.
If the thermal protection function is triggered, the power window motor can be reactivated after a waiting time of approx. t = 30 s (depending on the outside temperature).