"the compressed air sensor for the system has a malfunction, there is an implausible signal"

This one has been popping up and throwing the little image on the dash of the car with an arrow and "malfunction".

Any ideas of where to start?

Also, I've noticed the rear driver corner appears to sag quickly when parked. I'm guessing I should try and check out that rear air spring or replace it, however would like to isolate if there are any other likely leak points to go over prior to replacing the more expensive component.

Thank you in advance.

 

See attached bulletin...

 

Thank you. Naturally the only software I don't have access to is XENTRY :/.

Being that the rear right corner is indeed sagging, I will start there. In your experience, which components would you check first (most common failure point) air spring, valve, or line? Where is the compressor located in the 2010 e550 4matic?

Thank you.

 

Start at strut...

 

Do you mean start at the front strut and work to the rear of the vehicle? or start with the rear air spring and components surrounding that area.

2 other questions:
1.) Does the XENTRY system allow a scan/component test for the pressure systems in each portion of the car to isolate before using that mercedes leak spray (never worked with or seen this stuff before)?

2.) Is the compressor accessed from the exterior/bottom of the car or tucked inside of a panel on the interior?

I appreciate your help on this. The exploratory phase of these repairs for the first time is half "figure out where the hell everything is" vs just addressing the problems. If XENTRY really can access and isolate these problems much more efficiently, it may be worth picking one up. I already have the autel, and multiple snap on diagnostic computers available to me in my buddies shop, but he doesn't have the XENTRY yet.

Having built and owned several jeeps with arb air lockers, I'm no stranger to the dish soap and spray bottle, but before I spend a weekend going this route thought I would double check there is not an easier method!

 

This is an interesting topic for me as I also have a 2010 E550 with Airmatic.


You say that the car drops down quickly after you shut it off. Can you hear the air leaking out and if you do can you locate it? When the spring empties itself the air goes somewhere, right.


What I would do is first find where the air goes to. You could have a simple air tube connection leak or a hole on the tube. In these cases the compressor would be running basically at all times when the car is running.


If you don't find a leak on the lines I would check the valve for that dropping air spring. If it doesn't close it will let the spring empty just like a leak on tube.


I had an issue with the rear of the car dropping over night and it was repaired under warranty. MB has a service bulletin for this that explains the rear air springs is a faulty design and it was replaced with a better design. Wonder if your car has had this job done? I guess you are outside of warranty but perhaps MB can help if the service bulletin job was never done to your car...?

 

Thank you. Basically you put the car in park than hear the hiss and it settles. I'll see what I can find. My best friend that is an Indyus willing to buy a xentry. I think I am officially spoiled.

Still I wonder if it will actually offer him anything of value. If snap on had an eating disorder, you could see his tool cabinet. .

 

When you park the car and turn off the engine it is normal to hear the "hiss" as the car lowers back to the set height. Driving pulls car down and it pumps more air in the springs but when you stop the down force goes away and car raises up above the set level and it lets air out to get to the proper level again.


Your problem is air getting out from the spring after this "hiss" sound that you hear. I'm starting to believe you have the same problem that I had involving a faulty seal design on the rear springs...

 

I've noticed the passenger side of the vehicle sits about an inch and a half higher than the drivers side. I had a repeat of the initial 155664 code along with a code once regarding a valve malfunction of the front passenger valve

I scanned the car again after addressing a few other things (Wheel spacers, and fixing the rear sunshade).

I can no longer get any code whatsoever from the airmatic system. It doesn't appear to recognize it is is the car at all. I've carefully watched as the scanner rolls through everything and systems not present fall off.... those that check ok are logged. The airmatic system just seems to be missing (wouldn't that be nice)

I tried both a snapon modis ultra, as well as the Autel maxisys (which had previously pulled airmatic codes).

This time I noticed a few other things I had not seen previously regarding esp/ads which are related to suspension. Simply the normal "airmatic" system did not appear in any way shape or form, good or bad

If I switch between the sport and comfort modes the car raises and lowers. If I pull the airmatic relay, I get the malfunction warning on the dash but does not trigger the airmatic to show up in either scan tool.

Any ideas or something I can try to troubleshoot this without throwing money at parts/modules?

I just want my car to sit level so I can start doing the "fun" mods like wheels/stereo/customization vs chasing demons.

Thank you in advance

 

hi did you fix the problem? my gl had the same problem like you, I can't find any leak or damaged sensor or line. the only thing I think of is the height sensor link would be next. PLS let me know how did you solve that problelm
Thanks in advance

 

I would suggest you look under W220 for airmatic info, the encyclopedia will walk you through the diagnostic process, there are many components to this system that can cause problems, but well worth it for ride Quality,

 

Reviving this topic in case anyone is able to help.

I've been struggling with my airmatic system for a couple of months on my 2010 E550 (with 95K miles) with no luck. I'm getting DTC C155664. So far the dealer replaced front right shock under warranty about 3 years ago and I replaced the front left myself outside of warranty about 2 years ago. Last year I replaced both rear airbags with Arnott bags due to leaks and the car dropping overnight. Everything was working well after my repairs for at least a year until I started getting the airmatic malfunction indicator on my dash.

Last month I replaced the compressor, relay, and valve block with "Aerosus" parts. I also replaced the Airmatic Control Module hoping it would resolve the issue. This did not resolve the problem so I purchased a bidirectional Autel OBDII scan tool that has allowed me to look at specific data. I have absolutely no leaks (including microleaks) proven by the fact that my car doesn't drop at all after several days (up to a week) of not driving it. I've looked at lines and connections with leak detection spray, and I have no leaks.

Upon starting the car, the compressor comes on until the ECU is satisfied and it doesn't come on again until I start moving. I can clearly hear the compressor kick-on as soon as I start driving, and I can hear it cycle on and off continuously for a long time until the malfunction indicator comes on again. My Autel scanner tells me that voltages from the accelerometers, damping valves, and level sensors are within the acceptable range.

Does anyone have any ideas? I'm getting ready to throw-in the towel and go to the dealer, but I fear they'll tell me they can't help because I've thrown aftermarket parts on the car.

Thanks in advance!

 

That frustrating @mdreef ... I'm dealing with some airmatic issues on my '11 E550 as well and just finished dealing with them on our E350 wagon as well.

When you replaced the airmatic module, was that performed by dealer? Look at the bulletin posted by @konigstiger (post #2). The dealer will run a bunch of tests with Xentry, usually something will fail. If nothing fails, they reflash the airmatic module with later software. So i'm wondering if you might have the newer software, again you'd need Xentry to verify.

I don't have much to offer more, I have Xentry and the E550 passes all tests... yet the rear end still drops overnight. So its not the end-all diagnostic tool. It did however reveal odd behaviour of the valve body, which turns out has a micro leak when checking the compressor line (with no input to valve body).

*edit*

Actually come to think of something, have you checked for leaks between the valve body and reservoir? The only reason the compressor comes on, IIRC, is low-pressure in reservoir. So unless, every start the suspension needs adjustment (draws down reservoir) and/or leak in "system". That's one leak, which wouldn't cause a drop in suspension height (assuming the valve body was "good").

 

Thank you for your good advice - all good thoughts!
I purchased the ECM used for $75 on ebay as I didn't want to spend a lot of money ($500) if it wasn't the problem. I figured the car that originally had the ECU would have gotten the software update, although that's obviously a huge assumption. Either way, swapping it didn't change the behavior of my airmatic system at all, so I can deduct that the ECM is most likely not at fault.

I did check the line between the valve block and the reservoir with no leaks, although I have to admit there's a portion of line that's not accessible nor visible. What makes me think that I don't have a leak anywhere in the system is the following:

1. The car doesn't drop at all in any corner
2. Applying leak detection spray revealed no leaks
3. When I start my car after an overnight rest, the compressor doesn't come on at all - even when I'm just idling for a few minutes. This tells me that the system must be satisfied with the amount of air in the reservoir as well as the levels on all corners.

The most confusing part is the fact that the compressor comes on once I start moving. It's random. Sometimes it comes on right away, and sometimes it comes on after driving a half mile. It often comes on for about 15 to 30 seconds with a few follow-up short 1 to 2 second spurts (sometimes up to 5 spurts).

I'm about to go insane with this issue!

Thanks again for your advice.

 

The code your getting, C155664 "The compressed air sensor for system pressure has a malfunction. There is an implausible signal.", do we know thats related to excessive compressor cycling?

The Airmatic will continually adjust the suspension as you drive it... so that's not abnormal (for compressor to cycle while driving). One automatic function is lowering the vehicle over a certain speed and then raising when speeds reduce. Now how active the system is, I guess depends. Last time I looked at the compressor ON time was > 1,000,000 (in seconds) using my Launch. Even our wagon was high (maybe an order of magnitude lower), considering only 1 axle, lack of "height" control (lowered, normal, comfort or raised) and not certain on lowering with speed function.

So 1 million seconds, 100k on e550 = 10 seconds of compressor ON time for every mile driven.

I'll double check with Xentry, I know I saw a big number when I was running some of the airmatic tests... Assuming its correct, its likely skew'd a little since the car has had a leak for unknown period of time.

 

I wonder if MB publishes code setting criteria? @konigstiger thoughts? Watching a lot of SMA and PHAD, often theyll pull up service data and see the code setting criteria to better understand why it might be getting tripped.

 

@mdreef at this point, you've done so much work and $$, the bulletin posted only leaves one more thing you haven't done which is updating the software. I would bring the printout to dealer or indy (with STAR/account to program), explain the situation, they'll run the tests, hopefully they pass and they'll update the software. It should take less than an hour, but 1-2hrs charge I'd suspect.

 

I ended up just fully replacing my AIRMATIC suspension with coilovers. I didn't want to have to, I really like the air suspension and being able to easily (with the press of a button!) adjust the stiffness and height... but it had been failing for a while and I've had so many OEM parts on this fail that I just had it ripped out and replaced. Ended up with a really low ride (I actually bottomed out on the rear leaving a parking lot, I think for the first time in my life), and stiff suspension. The front is a little higher, but the shop said it'll settle a bit. So far I'm pretty happy, but I'm holding on to the air ride parts so I can have them rebuilt at some point (maybe).

 

Yes I fought the good fight through two cars, this is one of the reasons I traded in my '07 S550, was constantly having issues, way more than my '03 S500, which incidentally had the whole system replaced over the 12 years I owned it. absolutely the reason I got an E350 with none of that suspension crap, yes they were the best riding cars I ever had, just got tired of the problems in the '07 which was one after the other, yes they were under warranty, at least on that car, but the 16 dealer visits in four years was just too much.
I surrendered and sold the car with 30k miles and five years old. Was originally my plan to keep it for 5-7 more years, oh well, live and learn.

 

Hi there, i've read through all these comments and still can't find the solution. The problem i had was the driver front air strut air bag blew and the car dropped on that side. I replaced the air strut with the Arnott front strut and the car sits and rides perfect but the malfunction is still there. My indy ran all the tests he could possibly run with no success of clearing the Airmatic fault code C155664. I don't know what else to do to clear that frustrating code. Has anyone figured out the solution since the last post. I'm tempted to change the valve solenoid block in the rear but afraid i'd be wasting my money.

 

did you try pulling the negative battery cable for a couple hours? After clearing all the codes? If that doesn't work I believe you will need a trip to the dealer to reset the module. My '07 S550 was like this too,took a few warranty visits to work it out

 

no I didn’t try that but I will give it a go. Sorry but which module is to be reset?

 

Pierre,
Your airmatic is this kind of dampers ? :









My friend's Dad passed away and there is a 2008 S-Class W221 S350 with M272 3.5L NA engine and these dampers which my friend asked me if its okey he take over the car.
I look at the feared airmatic in detail and it is not the crazy expensive ABC type hydraulic based suspension and I told him I am up to the challenge to make the car drive worthy again.
Now it is not yet leaking yet, but car is in Surabaya city which is 800KM away and I plan to see the car this Sunday with him, driving my E400 there while at it, so that my car can get some mileage it deserve so badly this year

I will probably log pressure changes on the system with a BANKS iGauge if I own such a car...
2 locations to monitor pressure would be a great real time constant diagnostic.
If no buggy crazy software, pneumatic or hydraulic is much easier to troubleshoot than whacky electronic boards doing something bad but intermittent and we don't see any trace of what actually went wrong.

Is the airmatic computer module itself robust in your experience ?

Thanks

 

 

Arnott reputation has gone down a lot the last many years, according to those who used them often.
I won't be suprised if all Arnott does is reconditioning and not brand new 100%.

Watch here and this guy is not a bad-mouth person and was MB dealer tech.




.
Bilstein is German made, I will take Bilstein anyday and is using ordinary B4 and B6 on my own E400.