GF91.25-P-2003LE Adjust Rear Multicontour Seats, Function

GF91.25-P-2003LE Adjust Rear Multicontour Seats, Function
- with CODE (406) Rear multicontour seat as of Model Year 2009 /YoM 08

Function requirements, general
^ Circuit 15R or circuit 15 ON
^ Pressure supply active
^ Status of pneumatics pump for multicontour seat (M40) on interior CAN (CAN B) OK

Function description for rear multicontour seat adjustment, general
The individual rear multicontour seats (MCS [MKS]) can be adjusted manually via the rear control panel control unit (N72/2). In doing so, the signals from the rear control panel control unit are read in via the telematics CAN (CAN A) by the COMAND control unit (A40/3) and sent via the central gateway control unit (N93) from the central CAN (CAN F) to the interior CAN.

The left rear multicontour backrest control unit (N32/20) or the right rear multicontour backrest control unit (N32/21) then receives the signals for the individual positions on the interior CAN. On vehicles with code (276) Memory in rear, the rear multicontour seat can be automatically adjusted via the left rear seat operation switch group (S55/1) or the right rear seat operation switch group (S55/2) or the adjusted positions can be saved.

The air cushions of the multicontour backrest are located:
- In the side area of seat backrest
- in the lumbar support area (lumbar area) (top, middle and bottom) of backrest

Lumbar support = curvature of spine in lumbar region.

Abort conditions
- Inflation or deflation timeout
- Leak in an air cushion with the corresponding function
- On-board electrical system emergency running mode

Blocking
When the following fault is active, the function is blocked for the running ignition sequence:
- Inflation or deflation timeout

The "Adjust rear multicontour seats" function enables the following subfunctions:
^ Adjustment of air cushion lateral support for armrest
^ Up/down adjustment of the lumbar support
^ +/- adjustment of the lumbar support

Additional functions also run in the background:
^ Deflating functions
^ Short-term and long-term control

Adjustment of air cushion lateral support for armrest
By pressing the left seat selection button (N72/2s12) or the right seat selection button (N72/2s13) in the RCP [HBF] control unit, the corresponding MCS can be selected. The seat contour armrest button (N72/2s14) enables the air cushions of the armrest to be manually adjusted by means of inflation or deflation.

The right and left air cushion for backrest lateral support can be jointly inflated by pressing the seat contour armrest button forward or deflated to a minimum pressure by sliding the seat contour armrest button backwards. In doing so, the pneumatic valve is opened after the minimum residual pressure p = 25 mbar is reached for no longer than t = 1 min (upon actuation).

Up/down adjustment of the lumbar support
Pressing the left seat selection button or the right seat selection button in the rear control panel control unit selects the corresponding multicontour seat. Pressing the rocker switch of the lumbar support height adjustment button (N72/2s16) forward or backward, changes the backrest contour in the lumbar area by deflating or inflating the 3 cushions according to a filed performance map for lumbar support up or down.

+/- adjustment of the lumbar support
Pressing the left seat selection button or the right seat selection button in the rear control panel control unit selects the corresponding multicontour seat. By actuating the rocker switch on the lumbar support seat contour button (N72/2s15) toward the front or rear, the three lumbar air cushions are inflated or deflated manually to change the backrest contour. Pulling the rocker switch enables the lumbar support cushions to be deflated to minimum pressure. In doing so, the pneumatic valve is opened after the minimum residual pressure p = 25 mbar is reached for no longer than t = 1 min (upon actuation).

Deflating functions
The cushions in the lumbar area are overlapping, and thus their function is linked during the wave sequence. Since only one air cushion is active, the adjacent cushions are considered to be inactive (empty).

The following deflating functions are required to ensure this:
- Limit stop deflation (deflation timeout)

Limit stop deflation (deflation timeout)
If moved towards stage "0", the cushions can be deflated to minimum pressure. In doing so, the pneumatic valve is opened after the minimum residual pressure p = 25 mbar is reached for no longer than t = 1 min (upon actuation).

Short-term and long-term control

Additional function requirements
- no adjustment active
- no pulse function (massage) active

The short-term control compensates for overpressure deviations in the air cushions. It activates following every adjustment and only remains active for a shorter, parameterizable period of time. This function is used among others to compensate for sitting down or leaning back immediately and in a comfort-oriented fashion.

After the short-term control, the long-term control becomes active. Here, the pressure supply is regulated such that the specified pressure is always achieved. This is done almost without the customer noticing.