Lumbar support adjusting facility, function - GF91.29-P-0011GD
MODEL 204.0/2 with CODE (275) Memory package (driver seat, steering column, mirrors) with CODE (242) Electrically adjustable front passenger seat with memory as of model year 2010/YoM 09
MODEL 204.3/9 with CODE (275) Memory package (driver seat, steering column, mirrors) with CODE (242) Electrically adjustable front passenger seat with memory
Function requirements, general
- No on-board electrical system limp-home mode
The rear SAM control unit transmits an on-board electrical system limp-home mode via interior CAN. The driver seat or front passenger seat control unit then switches off the power supply for the lumbar support adjustment.
Lumbar support adjustment, general
In order to provide optimum support for the vertebral column, the backrests on the driver and front passenger seats each contain a lumbar support unit.
The lumbar support unit comprises:
- Two air cushions,
- an electric lumbar support pneumatic pump for compressed air production and
- the lumbar support adjusting facility control unit with integrated control valve block for pneumatic control.
The adjustment is performed via the lumbar support adjustment switch, which is connected to the lumbar support adjusting facility control unit via a direct electrical line and is located on the exit side of the seat.
The lumbar support adjustment comprises the following partial functions:
- Function sequence for filling the air cushions
- Function sequence for deflating the air cushions
- Function sequence for height adjustment of the lumbar support contour
Function sequence for filling the air cushions
As long as the cross-shaped rocker button of the lumbar support adjusting facility switch is pressed in the "forward arrow" direction, the backrest contour in the lumbar support area is changed by inflating the currently active upper or lower lumbar support air cushions. The differences in pressure in the individual cushions are retained. On reaching the maximum pressure, the inflation is stopped.
Function sequence for deflating the air cushions
As long as the cross-shaped rocker button in the lumbar support adjustment switch is pressed in the "backward arrow" direction, the lumbar support contour is changed by deflating the air cushions. The deflation starts with the upper air cushion, t = 1 s ahead of the lower air cushion.
Function sequence for height adjustment of the lumbar support contour
When the cross-shaped rocker button of the lumbar support adjusting facility switch is pressed up or down, the lower or upper air cushion is activated and inflated or deflated separately depending on the request. In this case, deflation of one of the cushions starts approx. t = 2 s before inflation of the other cushion that has been activated.
When the cross-shaped rocker button is pressed in the "upward arrow" direction, the air pressure increases in the upper air cushion area and drops in the lower air cushion area.
When the cross-shaped rocker button is pressed in the "downward arrow" direction, the air pressure drops in the upper air cushion area and increases in the lower air cushion area.
The supply of compressed air is distributed by the lumbar support adjusting facility control unit via the pneumatic lines to the upper and lower air cushion to match the driver's need.
The pressure is also regulated by the lumbar support adjusting facility control unit.
| Electrical function schematic for lumbar support adjustment | PE91.29-P-2051-97FAA | ||
| Overview of system components, electric seats | GF91.29-P-9992CE |