Windows: Description and Operation
GF72.29-P-0003CE 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)
Power windows (PW), general
The side windows in the front and rear doors can be opened and closed with the power windows.
The convenience feature is a possibility to open and close the side windows from one central control point. These function are described in the separate function description for the "Convenience feature (CF)".
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 thermal protection
^ Priority function sequence
Automatic closing is additionally described in the PRE-SAFE function description and automatic opening in the supplement restraint system function description.
Operation possibilities:
The following switches can be operated via the driver side power window and outside mirror adjustment switch group (S20
- Left front power window switch (S20s1)
- Right front power window switch (S20s2)
- Left rear power window switch (S20s3)
- Right rear power window switch (S20s4)
Individual side windows can be opened and closed from the driver position with these switches.
Only the corresponding side window can be opened and closed via the passenger side power window switch (S21/2), left rear power window switch (S21/3) and right rear power window switch (S21/4
Operation via the left/right rear power window switch can be inhibited by the rear side window child safely lock switch (S20s5).
Side window adjustments activated by the power window lifter can be interrupted by other higher priority operation points.
The circuit status c. 15R is provided by the electronic ignition lock control unit (N73) on the interior CAN (CAN B). The status of the front doors is recognized by the left front door lock (A85) or the right front door lock (A85/1), read in by the left front door control unit (N69/1) or right front door control unit (N69/2) and stored on the interior CAN.
Additional function requirements for manual raising and lowering
^ Power windows normalized
^ Child safety lock switched off (only for rear side 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 position of the power window switches in the driver side switch group is read in by the left front door control unit via left door LIN (LIN B5).
The switch position of the driver side, passenger side power window switch is read in by the right front door control unit. The switch position of the left rear power window switch is read in by the left rear door control unit and the switch position of the right power window switch by the right rear door control unit.
The corresponding front and rear door control unit then actuates the following components:
- Left front door power window motor (M10/3)
- Right front door power window motor (M10/4)
- Left rear door power window motor (M10/5)
- Right rear door power window motor (M10/6)
Actuation of the power window motors is limited to max. t = 25 s.
Actuation takes places for as long as the corresponding request is maintained or until the side window reaches the lower or upper stop.
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.
Function sequence for child safety lock
When child safety lock (rear side window child safety lock switch pressed) is switched on, no actions are performed by actuation of the rear power window switches.
Actuations already activated are interrupted immediately.
The status of the rear side window child safety lock switch is read in by the left front door control unit via the left door LIN and transmitted to the left rear door control unit and right rear door control unit via the interior CAN.
If the child safely 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 counters in the front and rear door control unit evaluates the signals from the corresponding Hall sensors in the power window motors.
The zero position is the upper stop (side window fully closed) and is set by the normalization procedure.
Depending on the actuation direction, the counter status is increased when "opening" and decreased when "closing" the side windows.
Normalization function sequence
Normalization means teaching in the upper mechanical side window stop (zero point) into the corresponding front door and rear door control unit.
For this purpose completely close corresponding side window wit the manual raising function. After releasing the power window switch, the side window lowers approx. s = 20 mm. Now it is necessary to reactuate the power window switch manually within t = 4 s and continue to actuate the power window switch for t > 300 ms when the side window has reached the upper end position.
The location counter is then reset to z = 0 in the corresponding front door and rear door control unit.
Function sequence for denormalization
The power windows are denormalized under the following conditions:
- The front and rear door control unit recognize a location counter status greater than the maximum side window travel.
- The front and rear door control unit recognize a location counter beyond the tolerance of the zero point stored
- The front or rear door control unit does not recognize Hall sensors signals when the corresponding power window motor is actuated.
The cause for denormalization is stored in the front and rear door 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, while raising a side window, the front or rear door control unit recognizes an increase in force or the Hall sensor signals do not change; this is evaluated as pinching. Raising is immediately stop and the side window is opens automatically.
The anti-pinch protection function is activated depending on the type of raising (automatic/manual).
The partial function anti-pinch protection comprises the following subfunctions:
^ 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
^ Inside opening of side window (s = 4 to 230 mm) within active range of excess force limiter
Function sequence for anti-pinch protection after manual actuation
The anti-pinch protection is active in three stages during manual raising.
If pinching (overload) is recognized by the front or rear door control unit, the actuation is interrupted and the side window is opened max. s = 20 when the switch is released.
If a new request is present within t = 4 s, the threshold of the excess force limiter is increased by one. If pinching is recognized again, actuation is interrupted and the side window opens s = 20 mm. if a request is present again within t = 4 s after the second stop, the window is closed without excess force limiter.
Function sequence for anti-pinch protection after automatic actuation
If the front and rear door control unit recognizes pinching, the actuation of the corresponding power window motor is interrupted and the side window opens immediately. When a new request is present within t = 4 s, the operation is again interrupted and the window is then opened. When a new request is present within 2 s after the second request, only manual closing is possible.
When the power windows are not normalized, the excess force limiter is actuated within t = 2 s after the second actuation. This allows normalization at the upper stop.
Function sequence for thermal protection
The power window motors are protected by a software-based thermal protection function in the respective front and rear door control unit.
This temperature of the power window motors is calculated in consideration of the voltage, current and duration of actuation as well as outside temperature
Priority function sequence
1. Driver-side switch group
2. Remaining power window switches
3. Actuation via STAR DIAGNOSIS
4. Close side window with PRE-SAFE (with code (299) PRE-SAFE)
5. Open side window with crash ventilation
6. Convenience opening/closing via transmitter key (A8/1)
7. Convenience opening/closing via recirculated air function
A command with higher priority is performed if a power window function with lower priority is already active.
The function with the lower priority is then interrupted.
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.
To allow full operation of the side windows even after the ignition is switched off, the power window functions have a run-on time of max. t = 5 min. This run-on time is ended prematurely if the driver or front passenger door is opened.
