I had a 2009 S550 with the same problem. It turns out that there is a software update that corrects this. Additionally, some seats require an electronic board swapout.
1) do you mean the left/right multicontour backrest control unit?Ok the engineer has undertaken the following checks and we are both definitely stuck - HELP !!!!!
1) He's opened up the back seat and tried swapping the lumbar switch from passenger to driver's side and vice versa - it's not the switch ...
2) He's opened up the boot and got to the pump. He's tried switching over the pipes into the pump and this doesn't make the driver's side work either.
3) Suspicion that it is an electrical fault - why? Well, he can see the voltage rise on the passenger side when one rotates the comand wheel on the centre console. If he does the same excercise on the driver's side then there is no voltage change detected.
4) ALL tests using STAR show no problems - in fact we're genuinely stuck WHERE on STAR one can find/test the lumbar function - it's not under ELECTRIC SEATS or CONTOUR SEATS or SAM etc. Any ideas anyone?
So in essence we are genuinely stuck. We can't detect any errors / fault codes under STAR and yet there clearly is a problem that the Comand does not appear to allow the triggering on/off of the driver's lumbar seat function.
ANY CLUES ANYONE ??????????????
MBUSA released Service Campaign 2006090002 SEPT06 updating seat control-unit software to correct memory loss that may be applicable. Have MB dealer check to see if your vehicle is included in VIN range if so, campaigns do not expire so update is free.So, where is the exact setting (if any) on the W221 STAR Diagnosis?
Do you mean the seat control unit or the lumbar support control module N32/24?Hi there - can confirm that I already have the latest update for the seats. What I'm trying to find out is where is the submenu on STAR that allows access for testing the Lumbar function?
The engineer has searched everywhere and suspects that you can't access it as the wire leading to the Lumbar control unit on the back of the seat rest does NOT appear to have a typical wire in the connector for communication.
And if we disconnect the control box, it does not appear to flag up an error on STAR. Please keep in mind that I have a STANDARD W221 seat not dynamic and not multicontour.
First of all, I would assume the version coding for the lumbar support should already be OK but you could check this if there are no other ideas explaining the lack of Star menu for this feature.Hi there. In reference to the question: "Do you mean the seat control unit or the lumbar support control module N32/24? The answer is the lumbar support control module N32/N24 located in the middle of the backrest when you remove the seat backrest using the two screws from the backrest underside
WHEN YOU SAY:
At least I could find the lumbar support actuation test from DAS, from the seat control unit menus. But I had to code the simulated car for lumbar support present first, perhaps the control unit has lost the correct coding at SW update.
How do you do this please, ie. how do you code the car for lumbar support? The engineer is connecting my car up to STAR and then entering the VIN number before diagnosing. What additional steps does he need to take in order to code it as you say for lumbar support?
Ive Got the same problem.First of all, I would assume the version coding for the lumbar support should already be OK but you could check this if there are no other ideas explaining the lack of Star menu for this feature.
You can reach the version coding menu by selecting "Control units" after entering the VIN and getting connected with the car (no need to run the quick test).
Next select "Seats and doors" menu and from there either "ESA-FR" or "ESA-FL" depending on if you want to test the left or the right front seat.
Once at the seat menu, select "Control unit adaptations" and next "Read coding and change if necessary".
I have "Lumbar support adjustment" as the fourth entry on the list. If this setting is currently at "NOT PRESENT", change it to "PRESENT".
There should be another setting for "Pneumatic pump for lumbar support adjustment", this should be set to "Lumbar support adjustment with series pump".
At least after this you should be able to find from the "Actuations" menu the "Lumbar support adjustment" selection where you can test if the adjustments have any effect.
Would be interesting to hear how the seat control unit was coded. If the lumbar support was coded for "not present", that could explain no fault codes when the control unit was unplugged. On the other hand it would be strange how this setting could have changed (unless the old SW had a bug).