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.

 

Sounds to me more like a pneumatic valve issue, the air bags do not get inflated and the control unit detects no change in air pressure and does not store the setting because it detects a malfunction. Just speculating. Have the car diagnosed with Star.

 

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 ??????????????

 

1) do you mean the left/right multicontour backrest control unit?
2) I understand other settings on the seats work except the lumbar support setting at the driver's seat? Also the passenger seat works fine? Does not sound like the pump could have an issue.
3) I assume the control unit was swapped from one seat to the other but the valve unit remained at each seat. Doesn't it still sound like a valve issue?
4) my DAS has the multicontour/dynamic seat diagnosis at the Seats and doors menu, at Left/Right front dyhamic seat menu. From there on you can select Actuations, Backrest and any one of the three Lumbar supports (top, middle or bottom). Actually odd if any of the three does not work.

Anyway if you select one, Star inflates the cushion to a specified pressure level and you can also adjust it up and down. If there is no change in the cushions, I would assume Star reporting an error at the control unit or the valve unit is stuck. This same control unit adjusts the shoulder area support as well as the lateral support cushion. Would anyone of those respond correctly?

Did you go through the guided tests?

A previous message suggested updating the control unit software, did you try this or did the control unit already have the latest SW?

 

Please help - we really need an answer to this. Thx

 

Hi Diesel-Benz. Many thanks for your reply but I need to double-check something with you. I do not have Dynamic Seats - I have standard seats with a Lumbar function in the middle of the seat as the picture above shows - not a HIGH, MED and LOW lumbar.

So, where is the exact setting (if any) on the W221 STAR Diagnosis? The Merc engineer looking at my car is saying that he can't see a communication wire into the lumbar module or the pump behind the rear seats of the car in the boot. Therefore, this is why he suspects that there is no way of using STAR to test the lumbar - do you agree with this?

Also, can I double-check that you are aware that the car I have is not the older S-Class. It's the newer shape W221. I want to check this since a pneumztic valve issue seems to be something that may be common on the older S-Class as oppose to the W221 range. Many thx.

 

So, where is the exact setting (if any) on the W221 STAR Diagnosis?

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.

SDS procedure per bulletin: “Control units/Seats and doors”, select appropriate seat control unit, then press F2 to acknowledge “Normalization” if it appears. Navigate through menu path “Control unit adaptations / Control module programming / Hard disk” If normalization is not automatically performed select “Control unit adaptations / Normalization of all seat adjustment motors” then select F5 to start process. Verify that coding was updated by accessing “Control unit adaptations / Read coding and change if necessary”

 

My seats are defininitely NOT multicontour seats.

Many thanks.

 

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.

HELP !

 

Do you mean the seat control unit or the lumbar support control module N32/24?

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.

 

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 conencting 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?

Thx

 

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?

Thx

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).

 

Just to avoid any confusion on an earlier point, I don't think the issue is a problem with a software update. Before I can even attempt to STORE/SAVE the Lumbar position, Comand does not even appear to be talking to the Driver's side Lumbar (it talks fine to the passenger side). Therefore, it seems there is a communication problem with the Driver's side lumbar that needs resolution first and which doesn't appear to have any access from STAR for diagnosing. That's where we're all stuck. Thx

 

^I believe DB you are correct and the car seat has not been coded and therefore the computer cannot control something that does not exsist in the computers memory. Nor would it show any fault codes for something it cannot check.

 

Ok everyone - problem now SOLVED ... total thanks to Diesel Benz. Basically as Diesel Benz suggested, the car was not coded for Lumbar. As soon as we went into Star and changed the Lumbar setting from NOT PRESENT to PRESENT, bingo the Lumbar started behaving perfectly again ... a simple problem but one that has made everyone over here in the UK tear their hair out ...

So Diesel-Benz, your patience and perserverance in helping us with this has really paid off !!!

A VERY BIG THANK YOU AGAIN FROM EVERYONE HERE IN THE UK !!!

 

DB, job well done congratulations man:thumbsup:

 

:thumbsup: