Lumbar adjustment function - GF91.29-P-0008GN
MODEL 166 as of model year 2016 with CODE 275 (Memory package) without CODE 399 (Multicontour front seats with massage function)
MODEL 166 as of model year 2016 with CODE 560 (Electrically adjustable front seats) without CODE 399 (Multicontour front seats with massage function)
MODEL 166 as of model year 2016 with CODE P64 (Memory package) without CODE 399 (Multicontour front seats with massage function)
MODEL 292 with CODE 275 (Memory package) without CODE 399 (Multicontour front seats with massage function)
MODEL 292 with CODE 560 (Electrically adjustable front seats) without CODE 399 (Multicontour front seats with massage function)
MODEL 292 with CODE P64 (Memory package) without CODE 399 (Multicontour front seats with massage function)
Function requirements, general
- Circuit 30g On or run-on active
- No overvoltage or undervoltage
- No on-board electrical system limp-home mode
Power down:
If circuit 30g is switched off, the lumbar support remains adjustable for t = 180 s. If, during the run-on time, the circuit status or the door status is changed (open or close), the run-on time starts again.
The left front door control unit sends the status of the left front door over interior CAN to the SAM control unit. The right front door control unit sends the status of the right front door over interior CAN to the SAM control unit.
On-board electrical system limp-home mode is sent by the SAM control unit in vehicles with CODE 560 (Electrically adjustable front seats) via center console switch LIN and in vehicles with CODE 275 (Memory package) or CODE P64 (Memory package) via interior CAN to the driver seat control unit or the front passenger seat control unit.
The driver seat control unit or the front passenger seat control unit then switches off the power supply for the lumbar support adjustment.
Lumbar support adjustment, general
To achieve optimum support of the vertebral column, the backrest on the driver seat and front passenger seat is each equipped with a lumbar support unit.
The lumbar support unit consists of the following components:
- two air cushions
- Lumbar support pneumatic pump
- Lumbar support adjustment control unit
Function sequence for lumbar support adjustment
Setting is performed via the respective lumbar support adjustment switch. The lumbar support adjustment control unit reads in the status of the lumbar support adjustment switch directly and then actuates the corresponding lumbar support pneumatic pump for compressed air supply of the air cushions.
As long as the cross-shaped rocker button of the lumbar support adjustment switch is pressed in the "forward arrow" direction, the backrest contour in the lumbar support area is changed by inflating the upper and lower lumbar support air cushions. The pressure differential in the individual air cushions is maintained. On reaching the maximum pressure, the inflation is stopped.
As long as the cross-shaped rocker button of the lumbar support adjustment switch is pressed in the "backward arrow" direction, the backrest contour in the lumbar support area is changed by deflating the lumbar support air cushions. Deflation starts with the upper lumbar support air cushion with a time shift at t = 1 s before the lower lumbar support air cushion.
When the cross-shaped rocker button of the lumbar support adjustment switch is pressed up or down, the lower or upper lumbar support air cushion is activated and inflated or deflated separately according to the request.
- When the cross-shaped rocker button is pressed in the "upward arrow" direction, the air pressure increases in the upper and decreases in the lower lumbar support air cushion.
- When the cross-shaped rocker button is pressed in the "downward arrow" direction, the air pressure decreases in the upper and increases in the lower lumbar support air cushion.
Here, the deflation of the one lumbar support air cushion begins approx. t = 2 s before the inflation of the other lumbar support air cushion that is activated.
The compressed air supplied is distributed by the lumbar support adjustment control unit via the compressed air lines to the upper and lower lumbar support air cushion, depending on the request. The pressure is also regulated by the lumbar support adjustment control unit.
In the respective lumbar support adjustment control unit, pressure sensors are integrated that record the pressure values in the air cushions.
MODEL 166 as of model year 2016 with CODE 275 (Memory package) without CODE 399 (Multicontour front seats with massage function)
MODEL 166 as of model year 2016 with CODE P64 (Memory package) without CODE 399 (Multicontour front seats with massage function)
MODEL 292 with CODE 275 (Memory package) without CODE 399 (Multicontour front seats with massage function)
MODEL 292 with CODE P64 (Memory package) without CODE 399 (Multicontour front seats with massage function)
The memory function can be used to store the current setting for the lumbar support along with other settings and to actuate them when required. Detailed information concerning this can be found in the electrical seat adjustment function.
| Electrical function schematic, lumbar support adjustment | PE91.29-P-2055-97NBA |
| Overview of system components, electric seats | GF91.29-P-9992GN |