Gear Selector Switch

Gear Selector Switch (GWS)
The gear selector switch (GWS) enables selection of a drive position of the automatic transmission with Steptronic mode and Sport program. The GWS is positioned in the front area of the centre console of the vehicle and is designed as a separate control module.

Brief description of components
The GWS consists of function geometry (housing) and a selector lever with integrated function indicator.

Independently of the selector-lever position, the engaged drive position is shown in the function indicator.

The selector-lever position of the GWS is picked up by means of sensors without contact and forwarded via the PT-CAN to the transmission control (EGS). For reasons related to availability, these signals are also passed on across a the PT-CAN2 to the EGS.

The function display in the selector lever is designed as a shift diagram, showing the positions P, R, N, D, M/S. The engaged drive position is indicated in this shift diagram by means of LEDs. The display in the shift diagram only changes when the EGS has implemented the driver request and the GWS has confirmed this status via the bus. The GWS only displays what comes from the EGS in the form of signals.

Functionality of GWS
To engage a drive position after engine start-up, the selector lever must be pushed / overpushed towards rear or forward.

To engage the drive position R, alongside the brake operation, the unlock button on the side of the selector lever must be pressed.

P is removed from the shift diagram by means of a separate button in the selector lever. When the P button is activated and 'P engaged' signal comes from the EGS, the green LED for drive position P is activated by the GWS.

The GWS is mono-stable within the automatic gutter and within the Steptronic gutter, i.e. it keeps returning perceptibly to its initial position.

The gutter change is bi-stable. The gutter change into the manual gutter M/S from position D can be carried out manually at any time. There can be no gutter change from other positions.

If the P button is operated or P is automatically engaged by 'ignition off' and the GWS is still in the manual gutter (M/S), an actuator is automatically activated to return the selector lever to the mono-stable initial position of the automatic gutter.

The forward direction of movement of the selector lever towards and to the left towards M/S must be perceptibly blocked or released depending on initial position and status of the unlock button. Possible lever movements depending on the transmission position and activating of the unlock button:
- Switching into the manual gate:
A motion to the left into the manual gate is only possible from position D
- Transmission position P:
Movement of the lever is only possible with the unlock button activated
- Transmission position R:
One-touch and overpressing forwards is not possible, not even with the unlock button activated. One-touch and overpressing towards rear are always possible
- Transmission position N:
One-touch and overpressing forwards are only possible with the unlock button activated. One-touch and overpressing towards rear are always possible
- Transmission position D:
One-touch forwards is always possible. Overpressing forwards is only possible with the unlock button activated. One-touch and overpressing towards rear is not possible, not even with the unlock button activated.

The blocks only become active with terminal 15 and are deactivated in the idle state.

Special situations (functions in the EGS)

Memory function for driving direction change
Driver request from D to R or from R to D
- At v ≤ 5 kph, the driver request is implemented by the EGS
- At 5 ≤ v ≤ 10 kph, position N is engaged by the EGS. The position indicator switches to the driver request D or R. The driver request is stored. If a speed of 5 kph is undershot within 1 second, the driver request D or R is implemented by the EGS. If this speed is not undershot, position N remains display switches to N
- At v > 10 kph, N is engaged by the EGS

Memory function, parking lock
Driver request P
- At v ≤ 2 kph, P is engaged by the EGS
- At 2 ≤ v ≤ 5 kph, the current transmission position remains; the driver request is stored. If a speed of 2 kph is undershot within 1 second, P is engaged by the EGS.
- At v > 5 kph, the driver request is not accepted. The current transmission position remains and the CC message "transmission position P only at a standstill" is displayed

N holding phase
If position N is engaged at v ≤ 2 kph and engine off and the identification sensor is inserted, the N holding phase starts for 30 minutes. While this information is sent by the EGS, the display remains on and N lights up. At the end of the holding phase, the display flashes and the EGS engages P after 10 seconds (Auto P). If the selector lever of the GWS is moved during the N holding phase, the 30 minutes of the N holding phase start from the beginning.