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Power Windows (PW (EFH)), Function - GF72.29-S-0003TRA

Model 447 

Model 448 

G16501479Courtesy of MERCEDES-BENZ USA

Block diagram 

Function requirements, general 

IMPORTANT Run-on:

If circuit 15 is switched off, the power windows can still be operated for t = 5 minutes. If, during the run-on time, the circuits status or the door status is changed, the run-on time starts again.

The electronic ignition lock control unit (EZS) sends the status of circuit 15 via interior CAN to the left front door control units and right front door control units. The status of the corresponding front door (open or closed) is evaluated by the left front door control unit or right front door control unit.

Power windows (PW), general 

The side windows n the front doors or the vent window can be opened and closed with the power window lifters.

IMPORTANT Convenience features are available for opening or closing by opening or closing the side windows or vent windows from a central control point. The function is described in detail in the separate "Function description for theft protection and locking" in the partial function "Convenience feature (CF)".

Operation possibilities:

Press and hold down power window switch or vent window switch to perform a manual function. To start an automatic function it is sufficient to momentarily actuate beyond the catch point. Actuation is performed as long as (max. t = 25 s) the corresponding request is present or until the side window has reached the *  end stop.

Via the rear child safety switch (with CODE W32 (Electric passenger compartment vent window)) the control can be inhibited over the vent window switch.

IMPORTANT The priority of possible functions depends on their requirement. A command with higher priority is performed if a function with lower priority is currently active. A lower priority function is interrupted first and is accomplished only after the second valid request. 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 request before the corresponding function can be activated.

Priority sequence:

  1. Diver door control panel
  2. Remaining power window or vent window switches
  3. Actuation via diagnostic equipment
  4. Close window with PRE-SAFE (with CODE JP1 (PRE-SAFE))
  5. Open side window crash ventilation
  6. Convenience opening/closing through central locking
  7. Convenience opening/closing via recirculated air function

The power window function comprises the following partial functions:

Function sequence for normalization 

Normalizing is the basis for assigning the current position to the position of the side window sensed by the corresponding front door control unit. To this end, the corresponding side window must be completely closed manually, and the power window switch must continue to be pressed for approx. t = 300 ms. If the power window switch is then released, the side window lowers approx. s =20 mm. Now the side window must be closed completely within t= 4 s and the power window switch must be actuated for another t > 300 ms.

IMPORTANT The corresponding signal path is described in chapter "Manual opening and closing".

The location counter in the relevant front door control unit is set to z = 0 and the normalization is completed. The location counter evaluates the signals from the Hall sensor integrated in the corresponding power window motor. The counter status is increased when "opening" and decreased when "closing" the side window.

IMPORTANT The ratio between counter status and armature rotations of the power window motor is 4: 1.

The power windows are denormalized under the following conditions:

The cause for denormalization is stored in the corresponding front door control unit. When the power windows are denormalized, only the manual opening and closing functions are possible.

IMPORTANT Normalization is a basic requirement to use the entire power window functions.

Additional function requirements for manual opening and closing 

Function sequence for manual opening and closing 

Actuate and hold down corresponding power window switch or vent window switch to the first catch point or beyond in the opening or closing direction. Actuation is accomplished as long as (max. t = 25 s) the corresponding request is present or until the lower or upper stop is reached.

Front side window in driver side:

The status of the left front power window switch in the left front door control unit is read in by the left front door control unit over the left front door LIN. The left front door control unit then actuates the left front door power window motor and directly reads in the signals from the Hall sensor.

The status of the passenger side power window switch is read directly in by the right front door control unit. The right front door control unit then actuates the right front door power window motor and directly reads in the signals from the Hall sensor.

The status of the right front power window switch in the driver door control panel is read in by the left front door control unit via the front left door LIN and transmitted to the right front door control unit via the interior CAN. The right front door control unit then actuates the right front door power window motor and directly reads in the signals from the Hall sensor.

Rear vent window (with CODE W32 (Electric passenger compartment vent window)):

The status of the vent window switch is read in directly by the signal acquisition and actuation control unit (SAM). The signal acquisition and actuation control unit (SAM) then actuates the left vent window motor and right vent window motor and directly reads in the signals from the Hall sensor.

The status of the left vent window motor and right vent window motor in the driver door control panel is read in via the left front door LIN by the left front door control unit transmitted to the signal acquisition and actuation control unit (SAM) via the interior CAN. The signal acquisition and actuation control unit (SAM) then actuates the corresponding vent window motor and directly reads in the signals from the Hall sensor.

Additional function requirement for automatic opening and closing 

Function sequence for automatic opening and closing 

The corresponding power window switch or vent window switch must be actuated just beyond the first catch point in the opening or closing direction and then released.

IMPORTANT The remaining function sequence corresponds to that of manual raising and lowering.

IMPORTANT Actuation of the power window motors or vent window motors is discontinued automatically upon reaching the bottom or upper stop. During automatic raising (only for front side windows), the automatic reversing function is always active.

Model 447

(With Code W32 (Electric passenger compartment vent window))

Model 448

(With Code W32 (Electric passenger compartment vent window))

The rear vent windows can only be opened automatically. Automatic closing is not possible.

Additional function requirements for actuation by PRE-SAFE (With Code JP1 (PRE-SAFE)) 

Function sequence for actuation by PRE-SAFE (With Code JP1 (PRE-SAFE)) 

When the Electronic Stability Program control unit (EPS) recognizes an unstable driving status (e.g. understeer or oversteer), the side windows are closed to a defined position (s = 50 mm ± 4 mm before the upper limit stop) to minimize the risk of injuries).

The electronic stability program control unit (ESP) transits the request for PRE-SAFE adjustment via chassis CAN, electronic ignition lock control unit (EZS) and interior CAN to the left front door control unit and right front door control unit. The left front door control unit then actuates the left front power window motor and the right front door control unit the right front power window directly.

Actuation by PRE-SAFE is interrupted if:

Additional function requirements for crash ventilation 

Function sequence for crash ventilation 

Smoke particles are produced in the vehicle interior when the pyrotechnical restraint equipment is triggered. To ensure that the smoke particulates are quickly removed, the front side windows are automatically opened after an accident to a defined position (s = 50 mm ± 4 mm before the upper limit stop).

The supplemental restraint system control unit (SRS) sends the crash signal via the chassis CAN, electronic ignition lock control unit (EZS) and interior CAN to the front door control units. The front door control units then actuate the front door power window motors directly.

The crash ventilation is interrupted:

Crash ventilation is blocked for the following:

Additional function requirements for excess force limiter 

Function sequence for excess force limiter 

The excess force limiter function operates when the window is raised automatically or manually, however, at different sensitivity levels (escalation stages). The power consumption of the power window motor serves as a reference for excessive force.

The system is designed adaptively to prevent mechanical sluggishness being evaluated as pinching. This means that the system recognizes sluggishness by the increased current consumption of the specific power window motor and calculates an additional force of F = 10 N for the next request. This ensures a constant speed when opening or closing the power windows even in the face of advanced wear or external influences such as moisture and ice.

The adaptation is limited to a maximum value of F = 80 N. The individual escalation stages depend on the operating request and history and are shown in the table below.

IMPORTANT

Model 447

(With Code W32 (Electric passenger compartment vent window))

Model 448

(With Code W32 (Electric passenger compartment vent window))

Vehicles with rear electric vent windows are not equipped with excess force limiter for vent windows.

Manual closing 1st actuation (escalation stage 1) 2nd actuation (escalation stage 2) 3rd actuation (escalation stage 3)
Holding power window switches Stops at F = 100 N + 15 N Stops at F = 130 N + 15 N Actuation remains active
Releasing power window switches Reversing by s = 20 mm + 5 mm Reversing by s = 20 mm + 5 mm Actuation stopped
Automatic closing       
Releasing power window switches Stop at F = 60 N - 10 N; reversing s = 125 mm + 5 mm Stop at F = 80 N - 10 N; reversing by s = 125 mm + 5 mm Only manual raising possible

If the power window switch is actuated again within t ≤ 2 after completion of the reversing maneuver, the status changes. When the power window switch is actuated again after a time of t = 2 s, escalation stage 1 (1st actuation) is started.

If pinching is recognized during automatic raising triggered by the comfort closing function via the air recirculation function, the corresponding front door control unit with escalation stage 1 (1st actuation).

During automatic raising, actuated by the closing side window function, pinching is recognized by PRE-SAFE (with CODE JP1 (PRE-SAFE)), the corresponding front door control unit starts with escalation stage (2 (2nd actuation).

IMPORTANT When the power windows are not normalized, the excessive force limiter is activated starting at a pinching force of F = 100 N. The side window always reverses when it runs into the upper seal.

IMPORTANT On power windows which have not been normalized, the excess force limiter is deactivated within a short time after two closing requests. This allows normalization at the upper stop.

IMPORTANT Mechanical vibrations caused by bad road conditions are not recognized as pinching and do not lead to reversal of the corresponding power window. The "bad road recognition" required for this purpose is activated starting at a speed of > 8 km/h.

Additional function requirements for lock-up reversing 

Function sequence for lockup reversing 

If the front door control unit in question does not recognize any change in the Hall sensor signals within t = 150 + 20 ms or an increase in the force of F = 160 N while the side window is running up, this is evaluated as pinching. Raising is immediately stopped and the window opens s = 20 mm. The lock-up reversing function depends on the model of rolling up.

Escalation stages for excess force limiter function apply.

Function sequence for overheating protection 

The protection of the power window motors and vent window motors is guaranteed by an overheating protection software in the corresponding front door control unit or rear door control unit. The software simulates temperature characteristics depending on the operating time. The parameters required for this were determined in tests and are stored in the associated front door control unit or signal acquisition and actuation control unit (SAM).

IMPORTANT The permissible ambient temperature range of the power window motor is: T = -40°C to +85°C.

Function sequence for child safety lock (With Code W32 (Electric passenger compartment vent window)) 

When the child safety lock is switched on, it is not possible to open or close the vent window by actuating the vent window switch. Already activated actuations of the left and right vent window motors are immediately stopped. The child safety lock can be switched on and off via the rear child safety switch in the driver door control panel.

The status of the rear child safety lock is read by the left front door control unit via the front door LIN. The status of the child safety lock is transmitted by the left front door control unit to the signal acquisition and actuation module (SAM) via the interior CAN.

The rear child safety lock switch signals the driver that the child safety lock is activated. For this purpose, the left front door control unit sends a request to actuate the LED over the left front door LIN to the child safety lock switch.

IMPORTANT If the child safety lock switch can no longer be read with certainty, the child safety lock function is regarded as permanently switched on.

  Electrical function diagram for power windows Model 448 PE72.29-S-2050-97VDA
    Model 447 PE72.29-S-2050-97TRA
  Overview of system components for power windows (PW)   GF72.29-S-9997TRA 
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