Interior - Seat Air Cushion Doesn't Inflate
MULTI-CONTOUR/DYNAMIC SEAT AIR CUSHIONS NOT INFLATING OR BUBBLE FORMATION IN ONE OR MORE SEATS
Topic number LI91.25-P-046797
Version 2
Design group 91.25 Multicontour seat (MCS)
Date 12-08-2009
Validity Model 216.371/376/377/379/386, As of MY 07, VIN Range A002723 to A006715
Model 221.171/176/177/179/186, As of MY 07, VIN Range A106647 to A134746
Equipped with Option Code 406, 409 or 432 Multi-Contour Seats (MCS)
Reason for change Left Front Seat Cushion Adapter and Right Front Seat Cushion Adapter part designations switched / Supersedes DTB P-B-91.25/169a
Reason for block
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Complaint:
Multi-contour/Dynamic Seat Air Cushions Not Inflating or Bubble Formation in One or More Seats
Cause:
Inoperative transistors in the valve electronics (Figure 1).
Note:
Depending on the switch position of the valve, the air cushions may either over-inflate or not inflate at all even without interaction by the driver. To
remedy, follow the procedures below based on the specified fault code.
Attachments
Remedy:
Note:
Read the notes below very carefully prior to performing any repairs.
^ The comfort functions control units in the backrest of the pnuematic pump may only be replaced when all diagnostic and verification steps below
are performed and the inoperative conditions are present.
^ Do not replace the control unit under the seat cushion. It is not integrated in the comfort system and cannot cause any of the conditions referenced
above.
^ These specific conditions may only be caused by the valve electronics, and not by the pnuematic pump or the control unit.
^ DTC memory read-out and control unit programming must be performed in all cases.
Condition 1:
Check for the following stored DTCs in front left and right dynamic seat and rear left and right Multi-contour Backrest (Figures 2 and 3). Should
either of these codes be present, replace the corresponding unit.
DTC 9210: "System failure of Backrest Module Carrier"
DTC 8211: "System failure of Cushion Module Carrier"
Note:
On the front seats (Figures 2 and 3), the adapters (Module Carriers) in the backrest and seat cushions (Figures 4 and 5) for the
Multi-contour/dynamic seat function can be replaced separately. For the rear seat, the entire backrest pad should be replaced since the corresponding
modules are permanently integrated.
The following additional DTCs may be stored in the control units even for seats that are not affected.
DTC 9306: "Pump error"
DTC 9307: "Pump inactive"
These DTCs may be caused by the automatic shut-off of the pneumatic pump. In this case, do NOT replace any components on the corresponding
seat. Refer to Figures 6 and 7.
Condition 2:
Check for the following stored DTCs in the front and rear backrest massage pads (Figures 8 and 9).
DTC 9202: "The Module Carrier for the massage function is defective" which may be caused by inoperative valves in the massage pads.
Note:
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The massage pad in the front seats is integrated in the backrest pad, the entire backrest pad should be replaced should DTC 9202 occur. Due to the
inoperative valves in the massage pads, the following two DTCs may also occur.
DTC 9251: "Pressure loss detected due to a leak"
DTC 9250: "Pressure build up not possible due to a leak"
Should DTCs 9251 and 9250 occur in one of the dynamic Multi-contour seat control unit without DTC 9202, it may not be possible to immediately
identify the inoperative massage pad. For this condition, please follow the steps below (please read the steps first prior to starting).
- Delete the DTC memory in the pump control unit (dynamic seat pump).
- Isolate each seat with massage function from the pneumatic system; use each seat's connector which is separable.
On the front seats, separable connectors are accessed by removing the seat lining. On the rear seats, separable connectors are located behind the
backrests.
- Seal the separation point leading to the pump with blind plug, part number A124 805 02 44.
- Pressurize the system for at least 5 minutes.
Note:
During this time, do NOT operate any pneumatic functions; otherwise the pump control unit will not register the random air consumption.
5. If a seat with the inoperative massage function is isolated from the system, no DTC will be stored in the pump since random air loss is detected.
As a result, this identifies the inoperative massage pad.
- Replace the identified backrest pad (with integrated massage pads).
- After replacing the inoperative module carrier, control unit programming must be performed.
The following DTCs may also be stored in the pneumatic pump control unit (dynamic seat pump)
DTC 9180: "Pressure supply shut off via CAN signal from MCMS_FL"
DTC 9181: "Pressure supply shut off via CAN signal from MCMS_FR"
DTC 9182: "Pressure supply shut off via CAN signal from MCMS_RL"
DTC 9183: "Pressure supply shut off via CAN signal from MCMS_RR"
If one or more of these DTCs are stored in the pump control unit and if the inoperative parts cannot be replaced immediately, the entire pneumatic
system must be decommissioned by deactivating the pump via DAS. Under NO circumstances should the fault memory be erased and system
re-commissioned without first replacing the inoperative parts or deactivating the pump. The same applies in the event of significant over-inflation of
one or more air cushions (bubble formation).
(NOTE: For Part Number: Refer to EPC Group / Subgroup/Callout #)
Note:
The following allowable labor operations should be used when submitting a warranty claim for this repair. This information has been generated on
March 6, 2009. Please refer to Netstar -> Star TekInfo -> Star Time for the most current labor time allowance.
Attachments
Symptoms
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Page 279
Control unit/fault code
Page 280
Parts
Work units
Validity
Attachment - Figure 1
Page 281
Attachment - Figures 2, 3, 4, and 5
Attachment - Figure 6, 7, 8, and 9
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