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Could be a number of issues…
Not deflating is likely a stuck valve in the controls. Or bad software in the control module.
Deflating can be a leak in the lines, or the bladders, or valves. Or bad software.
When starting the car, you should hear the pump running and filling the pressure reservoir.
This pump runs on startup, and when the pressure drops below the threshold to run the bladders.
If it runs too long (due to leaks) it will shut off to protect the pump motor. This kills the system throwing a fault.
it MAY reset when restarting, or numerous restarts, or it may remain with a fault.
An SDS is helpful in tracking down the issues. A lot of fixes are simply looking and listening for leaks.
Good luck and be patient with the fixes. They take time to find and repair.
Last edited by kbob999; 11-17-2022 at 09:23 AM.
Reason: added info
Hoping this tip will help others with Dynamic Seat issues. I’m always looking for answers here to my problems, so I’m paying it forward.
My 2008 40K mile S550 had both seats setting back to zero every time I tested or set them. The SDS said leak in the system.
First leak was the blue line from the pump to the reservoir tank. Line was very hard, brittle, and had a circular split, possibly from heat? Replaced it by cutting 8” of the green line and splicing it in to the connectors. No pics. That seemed too easy.
But there was another leak, and it took a very quiet Sunday morning to listen for the air leaks while running the pump. Found it where the main line comes into the bottom of the passenger (right) seat on the right side of the seat. Line was inside the wire bundle tape, and was again hardened and split (see pics). Hardest part was getting the seat trim off without breaking it.
Old Line would not accept a splice coupling, as it continued to split. Replaced with...Lowe’s drip irrigation line. And it works great. But there were more leaks I could now hear!
The next was behind the Seat Back panel at the T, where the main line splits air to the seat cushion and seat back. There is a tiny ball pressed into a hole in the (weak brittle) plastic tee, and the plastic had split there. I considered an irrigation tee as replacement, but settled on a coat of 5 minute epoxy on the existing tee. Fixed it.
Now I can hear a leak in the seat back...likely from a bladder or another split hose or connector. That one is yet to be found, but the leak is small enough that all seat functions are working, and the pump does not ‘time out’ or overheat. Will share as I fix more fixes for issues.
mine seat just stopped working too. wonder how can i make the pump working to inspect the leakage?
the pump can be strange - it seems its on a thermal cut out - when you unlock the car at the start of the day in the boot you should hear the pump fire up (its behind the left rear passenger seat - hidden in the boot by the big flat trim at the back of the boot) - it should run for 30 to 60 seconds to get everything happy then if no leaks should remain off pretty much the whole trip - when you park up with the key out, around 5 mins in you should hear it dump some of the pressure so the air bags in the cushions have an easier life
if you don't listen out for the pump and just jump in clanging doors closed, rattling seat belts, creaking leather and cranking the engine up you may not have noticed it. If you have a significant leak it will cycle on and off every 7 mins or so for about 20 mins before over heating
at one point mine cut out and wouldn't get over it - the faults including an overheating pump error code wouldn't clear in diagnostics - as I poked fuses and scratched my head it came to life all of a sudden - I thought it was locked out in a low pressure so won't fire the pump situation - as it ONLY came back when I had squashed a lot of the cushions clambering about trying to reach the rear fuse panel in the arm rest (and I felt it was cutting back in as a certain pressure threshold was reached - which I could see changing on my handheld autel kit years back). But others here don't believe me - makes perfect sense forcing you back to a dealership "to do the job properly" in my mind....
an example of the the fun these give - on mine for 18 month the rear wouldn't clear a fault saying right backrest defective - just like the fronts like to do randomly - till you update the software or redo all the multiplug connections or just shout at it - but the rear seemed determined to remain "broken" - then as I was playing with dealer diagnostic kit last weekend I thought I'll see if that will get me anywhere - nope - so I sat in the back for the first time ever and bounced up and down kicked prodded and generally played about with all the buttons - dead - reports as dead - no response at all - so then I decided to run diagnostic test routines (in dealer kit) left side behaved then right side (the faulty one) part way through woke up a bit, played coy for a bit, then ran all tests and cleared all the faults and is back working again !!!
Thanks for all that contributed to this thread. I’m about to tackle much of the similar issues here and wanted to ask if anyone knew the outer diameter of the air line? I’d like to have purchased some before I start tearing down the seat. Thanks
Thanks for all that contributed to this thread. I’m about to tackle much of the similar issues here and wanted to ask if anyone knew the outer diameter of the air line? I’d like to have purchased some before I start tearing down the seat. Thanks
Edwin
I have some spare repair tails somewhere - I'd measure but not sure where they are at the minute - on dynamic multicontour massaging ones the pipes are double the size of the normal models... the whole tube of a basic e class fits in the inside diameter of the big boy seat's air pipes
but is stupidly not the standard festo industry std (its just smaller)
Did you just plug and play for the new updated control module, or did it need reprogramming? Did you buy new, or used for the module?
Originally Posted by kbob999
Update #2 on the dynamic seat repair, and more DIY fixes!
First off, the seat control modules for the 2007-2009 (?) have a couple different hardware/software versions. 2010 and later has the air valves and control module together as a unit.
The early version module for my '08 (221 870 77 86) is replaced by a later version (221 870 35 93). The later software version is "07/21/01", while the earlier one is "05/32/01".
Note the Production sequence is in the '200000' number range, not the '100000' or earlier versions.
When I replaced my early module version with the later software version, it solved the 'Return to Zero' issue when setting the dynamic seat.
Dynamic is now working!
Early Module Late Module
Next issue, the bladder was not inflating on the right bolster, only the left.
Testing shows the bladder holds air, so it was not a split seam in the bladder. Must be the valve to the bladder.
The valves can fail by not allowing inflation; or not allowing deflation.
I replaced a known good valve from a seat insert (bladders and valves). This valve replacement can be done by removing the seat back and control module, but it is tight.
Valve Labeling on image is S=Shoulder; RB=Right Bolster; LB=Left Bolster; M=Lumbar Middle
Once the defective valve was replaced, the right bladder worked in dynamic mode.
Another successful repair!
Valve Labels
Now on to the passenger seat for the same repairs. Hope this helps others with the same issues.
they are coded but they seem OK to work even though it may not have been...
I moved from original HW 05.15 running SW 2214422111 to SW 2169021900 - 09 07 no user discernable change, a few years later it was misbehaving like they randomly do, and I saw a later module going for nothing on ebay with three year newer HW 08.34 running the same software I now had, it worked for a bit then randomly played up like they do... had it SCN coded to the car, a year or so later it continued to randomly played up like they do
it was around the time this thread popped up, with another user saying he got just as much improvement by disconnecting the 6 multiplugs and refreshing the resistance it pretends to be offended by
it still comes up saying faulty now and then, but the functionality is all there - its just what these cars do - I wouldn't waste any time trying to look at it - if you read how my rear one woke up after an 18 month holiday above (in the last paragraph of post #28) I think that gives an insight the the sophistication of the cars electronics
The seat back module shown is plug and play...no coding required.
I purchased used from eBay. Make sure it is not from a flood vehicle or it is junk.
No luck for me on this issue. I finally got around to replacing the old module with the new/updated part running software 7/21/01. It must need a software update, because the massage function worked, but just barely--like it was inflating to 10% of capacity, and cycling through each bladder at that rate. Perhaps Benz Ninja could fix this for me.
While I was in there, I took an inventory of the many parts that have been replaced. The bladders bottom and top have been done, and lots of wiring. I'm assuming the cooling fans and/or heating function will fail at some point. Can anyone clafiy the following...are the fans included within the seat cushions, and the heater included within the leather covers?
fitted a new drivers seat squab on mine this year - just doable without removing the seats or unbolting anything - but not much fun
the 4 silly fans are part of the seat foam with the wires and fans part embedded in to the foam - and the foam on early cars is then bonded to the leather - but to me it looks easy enough on an old one to play as the foam is starting to to disintegrate as these are such well made cars ....
you can use PC fans they work perfectly well and the car has no idea you did this (might make sense to screw then on the the seat base from then top then have the foam cut back a tiny bit- might need to mount with rubber cushioning for noise / vibration) - as per a photo somewhere recently on this forum the whole leather and seat cover and foam squab just sit on top of a pressed metal seat base and the leather tucks in a groves with a cheap nasty bit of washing line that's sewn around the edge of some of the front and rear section of the leather cover - then the bits you could never reach to unclip with the seat bolted in the car you find around the sides just isn't there just a tacky bit of cloth stitched on that is dragged underneath to snag on a jagged bit of the seat base till it rips the cloth and stays there on both sides near the seat belt buckles - you can reach these with long needle nose pliers from below to release / refit the fabric
these have to be some of the cheapest most complex yet nastiest seats I have ever has the discomfort to sit on...
fitted a new drivers seat squab on mine this year - just doable without removing the seats or unbolting anything - but not much fun
the 4 silly fans are part of the seat foam with the wires and fans part embedded in to the foam - and the foam on early cars is then bonded to the leather - but to me it looks easy enough on an old one to play as the foam is starting to to disintegrate as these are such well made cars ....
you can use PC fans they work perfectly well and the car has no idea you did this (might make sense to screw then on the the seat base from then top then have the foam cut back a tiny bit- might need to mount with rubber cushioning for noise / vibration) - as per a photo somewhere recently on this forum the whole leather and seat cover and foam squab just sit on top of a pressed metal seat base and the leather tucks in a groves with a cheap nasty bit of washing line that's sewn around the edge of some of the front and rear section of the leather cover - then the bits you could never reach to unclip with the seat bolted in the car you find around the sides just isn't there just a tacky bit of cloth stitched on that is dragged underneath to snag on a jagged bit of the seat base till it rips the cloth and stays there on both sides near the seat belt buckles - you can reach these with long needle nose pliers from below to release / refit the fabric
these have to be some of the cheapest most complex yet nastiest seats I have ever has the discomfort to sit on...
Thanks for your reply....I had to Google squab...new word to me--young pigeon or cushion. Just curious...did you replace the squab because the foam was failing, or another reason?
when the car was 7 years old at 42k miles, two of the four fans on the drivers seat just fell off.... the housing still bonded in the foam, but half the motor and the fan was either dangling on wires or totally fell off - I fitted PC pans from beneath - but then only used that pointless feature about 2 times in the next 7 years, then 2 years ago the drivers heated seat on the squab just died at 65k miles...
as its a heated, vented, massage, multi contour, exclusive leather trim set up - I held out no hope in hell of finding one at a sensible price (over $1000 and unobtainable these days) - then worked out a passenger seat in europe LHD, where mine is RHD, could well have had much less exercise then a mutli mile scrapped car drivers seat will... started looking millions of wrong trim and type in USA on fleabay, but nothing for mine - then one popped up around Christmas (from one of the usual theft r us eastern europe countries) must be almost just in time manu as its only 7 month later - but all there and all working - nice to have heated seat again - makes such a difference when it less than 10 C out there
when the car was 7 years old at 42k miles, two of the four fans on the drivers seat just fell off.... the housing still bonded in the foam, but half the motor and the fan was either dangling on wires or totally fell off - I fitted PC pans from beneath - but then only used that pointless feature about 2 times in the next 7 years, then 2 years ago the drivers heated seat on the squab just died at 65k miles...
as its a heated, vented, massage, multi contour, exclusive leather trim set up - I held out no hope in hell of finding one at a sensible price (over $1000 and unobtainable these days) - then worked out a passenger seat in europe LHD, where mine is RHD, could well have had much less exercise then a mutli mile scrapped car drivers seat will... started looking millions of wrong trim and type in USA on fleabay, but nothing for mine - then one popped up around Christmas (from one of the usual theft r us eastern europe countries) must be almost just in time manu as its only 7 month later - but all there and all working - nice to have heated seat again - makes such a difference when it less than 10 C out there
So, do I understand correctly that you ended up with a new cushion from the shady eastern European supplier? I've seen them selling stuff on Ebay, and have wondered if they are legitimate. But isn't the heating element attached to the leather skin and not the cushion, or is that just the setup on the back cushion? The photos of the tear down are great but don't show that specific thing.
the parts from eastern europe are legit in what they are - the sourcing of is highly likely massive car theft and the open boarders of the EU
steal it in Germany drive overnight, strip it and fence it from Poland and Lithuania at your leisure - for them its like winning a rollover lottery everyday - and this can then fund some real big boy criminality (just as your governments really want)
police these days are paid not to stop crime but are solely there as enablers of such activity - all part of globalised thriving economy - where normal people get poor, as the rich screw it up and the criminals are the worker bees making it a success
not mine but it looked just like this ...
I buy shed loads of stuff that way - usually turns up faster than a UK supplier
the nightmare is buying stuff of ebay USA - most won't ship it, its taxed to death, your postal charges are stupid money, and the quick stuff takes three weeks to get here - and when you track it, most do a 1000 mile eight day sightseeing tour of USA depots, before being run over and lost for a further week - I don't agree with it - but we can buy direct from china, often shipping included in a cheaper price, delivered in 3 days, and no one cares about duties ?
I have this great 2008 W221 S550 4 Matic Long base wheel with 80,000 km ( about 50,000) . I bought it about 2 years ago and the dynamic seats with the massage function did work at the beginning but I could point out some issues from the first day as the Lumbar inflates and takes 2-3 days to inflate although I did put it to deflate . The second issue was with the cornering function with the seat support , the left side did not always return to it's supposed position (deflate) after driving straight although the right side works perfectly. other thing after 3 months the massage function stopped working , If I put the number of the desired massage it pops to 0 again . went to the authorized dealer , he resets the responsible computer and told me that they need to change the TEMIC module.
Yesterday I had time to test all this crab . took off the back seat cover of both front seats . and switched between the two seat TEMICS as the passenger seat has no issues . the result was the same . driver seat massage wont work .
So I Started checking the air pipes but the seemed to me all OK , although the massage wont work the other functions do work . i started comparing the two seats to discover electrical wires in yellow color all connected together and joined with plastic pipe to hold them together and they all should be directed to ONE TINY YELLOW WIRE that connects back to the computer module with black connector located to the far right side of the TEMIC . The TEMIC has 4 connectors from LEFT to the RIGHT .
1. small black Pin connector .
2. Big black pin connector .
3. white pin connector .
4. small black pin connector - (IT CONNECTS TO HERE)
The problematic wires getting out of the middle of the seat in between the two vents . about 8 yellow tiny wires rapped all together with hard transparent plastic to all join one tiny yellow wire (it seems to be ground ?? ) I took some pictures of the harness but it was late night sorry for the crappy pictures .
The solution was small screw (yes screw ) and piece of wire to connect between all the wires and the disconnected wire . I screwed the screw in the hard plastic where the disconnected small wire should be connected to . then joined the screw with the pieces of the new wire and the disconnected wire. The solution worked . The massage now work perfectly ...
Can you elaborate more on this piece, unclear from pictures, i have the same problem, bags inflate correctly and passenger side works fine for massage, but driver side massage doesnt work at all
The problematic wires getting out of the middle of the seat in between the two vents . about 8 yellow tiny wires rapped all together with hard transparent plastic to all join one tiny yellow wire (it seems to be ground ?? ) I took some pictures of the harness but it was late night sorry for the crappy pictures .
The solution was small screw (yes screw ) and piece of wire to connect between all the wires and the disconnected wire . I screwed the screw in the hard plastic where the disconnected small wire should be connected to . then joined the screw with the pieces of the new wire
Does anyone have any detailed advice on how to take the back of the CL550 seats off? The video above is for a S550 and the seats are not the same. Thanks!
This is a easy to do task. Raise the back of the seat up, and on the bottom of the seat cover you will find 2 torx screws on each side. Remove the screws and push down on the cover and it will pop off.
This is a easy to do task. Raise the back of the seat up, and on the bottom of the seat cover you will find 2 torx screws on each side. Remove the screws and push down on the cover and it will pop off.
My CL seat is in pieces on the garage floor right now. I'm putting it back together this morning. Let me know if you want me to check anything.
I had the same sporadic problem with my seats. I replaced both batteries which seemed to help some, but what seems to be holding steady is I raised the seats all the way up and reseated all of the electrical connections. I also checked to make sure all of the pins on the back side of the connection were firmly pushed in. I think sometimes when people vacuum or mess around under there, they may accidentally stress the connections enough so they make sporadic contact. Hope it helps.
I am having an issue with a stuck valve myself in my dynamic seat. How did you remove the valve from the module carrier? Are the air hoses heat sealed? How do they come off the remove a valve individually?
Hello,
I am having an issue with a stuck valve myself in my dynamic seat. How did you remove the valve from the module carrier? Are the air hoses heat sealed? How do they come off the remove a valve individually?
Thanks
vobak - the hoses can be hard to remove from the valves and fittings.
I had enough slack to cut the hose close to the valve, and reinstall the cut end on a new valve.
You could also heat the hoses and make them more pliable to remove/reinstall.
You could also punt and replace with irrigation tubing, which is the same size and lasts much longer. This is my current favorite for durable repairs.
Valves are recessed in the 'adaptor' and are held in by a sticky fabric tape. Not hard to replace this tape...use your imagination.
FYI - I'm getting new issues with the air pump timing out due to leaks. I'll need to start diagnosing the hoses/valves/bladders again for issues. Looks like they will never go away, just get better for a while.
Hi, Having finally retired I've found some time to try to fix the massage function in the driver's seat of my W221 S-Class. This was exactly the problem I found (along with a second wire that seemed to have been cut through). Thank you so much for taking the time to post about your repair. Mercedes had already extracted a lot of cash from me and got nowhere; even suggesting replacing lots of modules at some horrendous cost. Finally it took an hour of my time to sort out!
I've got my seat massager working reliably for one cycle, and then the screen shows "0" and will not restart, nor allow me to adjust other pneumatic seat functions. While looking at the system and hunting for leaks, I noticed the cylinders in the attached photo....does anyone know what those two cylinders are for? I don't believe I've seen mention of these previously.
11-10-2022, 07:18 PM
) I took some pictures of the harness but it was late night sorry for the crappy pictures .
