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Power windows (PW (EFH)), function - GF72.29-P-0003RF

Model 205, 253 

Fig 1: Power Windows (PW (EFH)) Block Diagram
G10134272Courtesy of MERCEDES-BENZ USA

Function requirements, general 

IMPORTANT Run-on:

If circuit 15R is switched off, the power windows can still be operated for t = 5 min. 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 transmits the circuit status of circuit 15 to the front door control units and rear door control units via the interior CAN (model 205.0/1/2, 253).

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 

For ventilation of the passenger compartment, the side windows of the vehicle can be opened and closed electrically.

IMPORTANT The convenience feature is a possibility to open and close the side windows from one central control point.

Operation possibilities:

Press and hold down power window switch to perform a manual function. To start an automatic function it is sufficient to momentarily actuate beyond the catch point. Actuation takes places for as long (maximum t = 25 s) as the corresponding request is pending or until the side window reaches the lower or upper stop.

In model 205.0/1/2, 253, operation of the rear power window switch can be inhibited via the rear side window child safety lock 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. Driver-side power window and outside mirror adjustment switch group
  2. Remaining power window switches
  3. Actuation via diagnostic tester
  4. Close side window with PRE-SAFE® (with CODE 299 (PRE-SAFE® system))
  5. Open side window with crash ventilation
  6. Convenience opening/closing through central locking
  7. Convenience opening/closing via recirculated air function

The power window functions comprise the following partial functions:

Function sequence for normalization 

Normalization is the basis for assignment of the current position relative to each side window position as detected by the front door control unit or the rear door control unit (model 205.0/1/2, 253). 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. The side window must then 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 the chapter "Manual raising and lowering".

The location counter in the relevant front door control unit or the rear door control unit (model 205.0/1/2, 253 is set to z = 0 and 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 windows.

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 reason for denormalization is stored in the corresponding front door control unit and rear door control unit (model 205.0/1/2, 253). When the power windows are denormalized, only the manual raising and lowering functions are possible.

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

Additional function requirements for manual raising and lowering 

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 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 power window switch group and driver side outside mirror adjustment are read in by the left front door control unit via the left 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.

Front side window in passenger side:

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 power window switch group and driver side outside mirror adjustment is read in by the left front door control unit via the 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 side window (model 205.0/1/2, 253):

The status of the rear power window switch is read in directly by the corresponding rear door control unit. The respective rear door control unit then actuates the relevant rear power window motor and reads in the signals from the Hall sensor directly.

The status of the rear power window switch in the power window switch group and driver side outside mirror adjustment is read in by the left front door control unit via the left door LIN and transmitted to the rear door control unit via the interior CAN. The respective rear door control unit then actuates the relevant rear power window motor and reads in the signals from the Hall sensor directly.

Additional function requirements for automatic raising and lowering 

Function sequence for automatic raising and lowering 

The corresponding power 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 is discontinued automatically upon reaching the bottom or top stop. The automatic reserving function is active during automatic raising.

Additional function requirements for actuation via PRE-SAFE (with CODE 299 (PRE-SAFE® system)) 

Function sequence for actuation via PRE-SAFE® (with CODE 299 (PRE-SAFE® system)) 

When the electronic stability program recognizes an unstable driving status (e.g. underride or oversteer), the side windows are closed to a defined position (s = 50 mm ±4 mm before the upper limit stop) before the upper limit stop to minimize injury risks).

The Electronic Stability Program control unit transmits the request for PRE-SAFE® setting via the chassis FlexRay, the electronic ignition lock control unit and the interior CAN to the front door control units and rear door control units (model 205.0/1/2, 253). The respective front door control unit then actuates the relevant front power window motor directly. The corresponding front door control unit (model 205.0/1/2, 253) then actuates directly the rear door power window motor.

Actuation by PRE-SAFE® is interrupted in case of:

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 sends the crash signal over the user interface CAN, electronic ignition lock control unit 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.

Manual closing  1. 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 or rear door control unit (model 205.0/1/2, 253) starts with escalation stage 1 (1st actuation).

If blocking is recognized during automatic raising, triggered by the KEYLESS-GO function (with CODE 889 (KEYLESS-GO) or side window closing function by PRE-SAFE® (with CODE 299) PRE-SAFE® system), the corresponding front door control unit or rear door control unit (model 205.0/1/2, 253) initiates 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 respective front door control unit or rear door control unit (model 205.0/1/2, 253) does not detect a change to the Hall sensor signal or a force increase of F = 160 N within t = 150 ms + 20 ms via the adjustment distance that is traveled when the side window is raised, raising is immediately stopped and the side window is opened s = 20 mm. The lock-up reversing function depends on the type of rolling up. Escalation stages for excess force limiter function apply.

Function sequence for overheating protection 

The protection of the power window motors is guaranteed by a thermal protection software in the corresponding front door control unit or rear door control unit (model 205.0/1/2, 253). 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 rear door control unit (model 205.0/1/2, 253).

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

Function sequence for child safety lock (model 205.0/1/2, 253) 

When the child safety lock is switched on, the rear side windows cannot be opened and closed by actuating the rear power window switch. Actuations already activated are interrupted immediately by the rear power window motors. The child safety lock can be switched on and off via the rear side window child safety switch in the power window switch group and driver side outside mirror adjustment. The status of the rear side window child safety lock is read by the left front door control unit via the front door LIN. The left front door control unit transmits the status of the child safety lock to the rear door control unit via the interior CAN.

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

IMPORTANT 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.

Electrical function diagram for power windows PE72.29-P-2050-97FBA 
Overview of system components for windows and sightproofing GF67.00-P-9999RF
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