Airmatic problems -- extremely hard ride -- help
 

Posting in the e55 section because the w164 forum is dead. The airmatic system in my ml63 is pretty similar to the e55 so maybe someone here can help me. Recently I noticed the ride in my 2007 ml63 is extremely hard and uncomfortable. My lowered e55 on 20" wheels was way more compliant over rough surfaces.. The ml rides like a skateboard. There is no difference between sport/comfort/raised/normal in the suspension settings, they all ride really hard. The first thing I tried was hook it up to STAR and test the various airmatic components. Everything checks out fine and there are no faults:

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Then I did a visual check of the springs/shocks/ air lines. It looked fine except the rear shocks which were leaking, so I replaced them with new OEM mercedes shocks.

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The ride is still extremely hard. I did however get this message a few days ago, but it hasn't appeared since then (I've never seen this error before in the ~6 months I've had this problem):

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At this point I'm leaning towards a ESP/airmatic/ADS module problem. Various searches revealed different solutions ranging from replacing the valve block/front shocks/computer but I don't want to start replacing random parts hoping to fix it yet. Is there a way in STAR developer to reset the airmatic or ads module? I played around in STAR a bit and managed to soften the damping through the actuations in the STAR developer menus but it doesn't hold the settings when you start the car. Any help is greatly appreciated.

Does the car make a thump sound or a thud sound going over bumps ?

If it does then it's probably a broken subframe bolt

Search Dead body thump.

I haven't heard any weird noises or thumps. I don't think its a mechanical problem. I took a look at all the bushings and ball joints and everything appears to be pretty tight. I'll take another look at the subframe bolts just in case but the car handles/steers fine, the ride/damping is just really really hard.

What is component N51? Maybe it has a short or something. I know on the W211 the airmatic computers go out all the time.

I think n51 is the airmatic computer. According to this bulletin by removing the airmatic fuse you can reset the airmatic computer. http://workshop-manuals.com/mercedes...n_rough_roads/ I don't have the thumping sound but I figured I would try this out. Maybe thats why I got that ESP CAN error message.

I also found this http://workshop-manuals.com/mercedes...ins/page_1323/ Unfortunately there is no fault code stored as described :nix:

Not looking forward to inspecting the module :( http://workshop-manuals.com/mercedes...ins/page_1317/

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Finally, I did notice I have a REAR SAM error. (open circuit, blown fuse). I'll try to get a picture later. This could be related to my problem: http://workshop-manuals.com/mercedes...ins/page_1321/

holy **** thats buried down in there! sounds like you're on the right track, hope you get it resolved!

Update-
So I took a look at the module, looks fine, no noticeable moisture. On the advice of another member I unplugged it for 15 min to maybe reset it. I put it back but the problem still remains.

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I also took it to the stealership but they weren't much help. They recommended I change the airmatic links as they are seized (???) for only $500 :rolf: I looked at the links and they are fine. I removed them and cleaned them just to be sure they move freely.

At this point I'm pretty much stumped I don't know what to do. I guess I'll keep my eyes open for a used airmatic module or maybe a new valve block...

I too am facing a super stiff suspension in my W164 ML350. My rear SAM module has failed too, but i'm not sure if there is a connecting link.

I'll let you know the results once i've changed the rear SAM module. I do suspect that is the cause of the super stiff ride (the suspension modes are making no difference to my car either. Its hard as a rock)

I managed to fix my rear sam problem. I was messing around with the coding of the rear SAM trying to enable the locking beep a few months ago and I must have done the coding wrong. I recoded it and now there is no error. My car still rides really hard so I don't think there was a connection for me. :nix: Hopefully you'll have better luck with your rear sam, let me know what you find.

I also bought a used airmatic computer from a GL550 (different car, exact same part number). I didn't transfer the coding from my unit to the gl unit, I just wanted to see how the car behaves with a different airmatic unit. The car rides WORSE with the gl unit... it is undrivable. This kind of leads me to believe my airmatic computer is working fine. At this point I'll probably replace the valve block and then the front struts and see if that helps.

http://www.google.com/translate?hl=e...-t4657404.html Someone else has also had this problem on a german MB forum. No solution posted :(

.trunzx: Thanks for the info on the SAM.

I had a similar problem with my W220- but only on one side. This was due to the level sensor on the front left shock being adjusted wrongly (The link had broken and i had tied it up using a wire- in order to prevent the car from getting too low. This was a temporary arrangement till the new links arrived.) The result was that the front left shock got super stiff as it was overpressurized. The problem was solved when i replaced the old links with new ones (and as a result, the height feedback was corrected).

When i contacted the dealership, i did not get any conclusive reply on this.

Incidentally, i have a leak on the front right shock of the W164- although i do not think that would be the cause either. The logical solutions i can think of are:

1. Shock absorbers not being good (Now this shouldn't happen to all 4 at the same time?)

2. Air springs being over pressurized (But then the car should be too high?)

3. Control issues on the airmatic struts- (There should be a solenoid valve to release pressure?) But this doesnt make sense due to point number 2.

I guess i do not understand the system too well yet.

Do keep me posted if there are any developments at your end.

Based on what I'm finding on other cars, it seems a leak in the front airmatic struts could lead to a hard ride. http://www.mbclub.co.uk/forums/wheel...unction-2.html Apparently the solenoid valves can leak and cause the ride to become hard. He only had one failed strut but it caused a bad ride.

I don't think it's an electronic problem as I get no error messages. If there was a broken wire or implausible reading from the level sensor I think it would throw a code. I don't believe it's a level sensor as the ride height looks good. The only thing I can think of is the pressure sensor in the valve block failing and reading too "high". If the pressure sensor is "off" by 1 bar or something, it can over-pressurize the system and cause a bad ride. This way the car wouldn't throw any codes as it assumes the pressure sensor is working correctly. That's my guess anyway :nix:

Here's what I found to solve this problem (on other cars, information on the w164 is limited), sorted by most common fix:

1.) Front struts
2.) Airmatic valve block
3.) Airmatic computer
4.) Airmatic compressor
5.) Acceleration/Ride height sensors
6.) Accumulators (not relevant on our cars)
7.) Rear SAM (Haven't found much information on rear SAM fixing this problem, but it does play a role in suspension based on information I posted above)

Check the Body Acelleration Sensor is so equipped
 

ON my E55, I had similar behavior after i got hit from behind. The car drove like it was in Sport II all the time. I unplugged the connector to the body acceleration sensor for the rear (passenger side wheel well), cleaned the connector and plugged it back in and car then rode smooth. I can't recall though if it tripped a code when it was riding harsh.
HTH.

hmm my car was in an accident before I bought it. I'll give this a shot see it helps. I unplugged the front sensor and got an error code so I think that one's working but I haven't tried unplugging the rear sensor yet.

Fingers crossed for ya
 

I had to drive my car that way to Chicago. Felt so stiff the whole ride, first thing I did after a 11 hour road trip was to jack the car, pop off the rear wheel and liner and unplug and replug that sensor. The drive back was much better as the suspension worked normally then.

it's a sign... time to go with coilovers... :naughty:

Have you hit anything hard lately? Years ago, I ran over a curb with the rear wheel on my E wagon. Immediately after that, it rode like a truck. The ride height didn't change, but you could stand on the rear bumper and the only thing that bounced was the tires.

If your ride height is fine, it sounds like you have the same issue that happened to me. In the airmatic strut, there is a seal that separates the air pressure coming in from the oil in the damper. This seal can rupture and consequently fill the air pressure system with oil from the strut. Oil doesn't compress nearly as much as air, so movement of the suspension system essentially stops.

This isn't an electronic problem, as all it controls is ride height. More air pressure and the car is too high, and less air pressure makes the car too low. Adding more air pressure doesn't make your suspension stiffer.

I do remember it being a pretty expensive curb.

I tried unplugging it today and unfortunately it didn't fix the ride :( Acceleration sensors are relatively cheap maybe I'll replace it just in case.

I'm considering it more and more at this point lol

I don't think I've hit anything recently, I think the car was like this when I bought it 2 years ago. At the time it was full of people and I was driving over unfamiliar roads so I didn't notice how harsh it was. Now that I drive the car by myself without the extra weight on roads I'm familiar with, I can definitely tell it's not normal.

That makes sense though. Looks like I'll be replacing the shocks on the front then, fingers crossed. :)

Hi guys, I am owner of an E55AMG'05. My car has an airmatic problem. The diagnosis gives these fault codes (5132-left side airmatic sensor/5142-right side airmatic sensor/5152-rear airmatic sensor)
Airmatic kompressor works fine up and down.
The problem is that car's left side is 12mm down then right side or opposite! (right side is 12mm upper then left side)
While we connect the car to diagnosis,we made felt and right at same balance but whenever disconnect from diagnosis and try to up or down the airmatic, the problem occurs again.
I think a wire contact to chasis,also deaits of the fault code says the same.
If somebody had the same problem,then help me where to start?
Thanks. I am sorry about my english,hope you understand well.
Note: sensors are fine,sockets are fine.

I am having the same problem and am leaning towards the speed sensor...i kno it can affect the abs/esp

Any update?
 

Hi .trunzx! Is there any update on the problem?

I am proceeding with changing the rear shocks as well (mine aren't leaking but it definitely feels as though they're on vacation).

Other than that i've heard the linear acceleration sensors could be acting funny; however, i do wonder if thats the case, and whether their live data is available on the star diagnosis (I haven't checked yet).

I'm facing another interesting situation- The front Airmatic leaks out air every now and then (front right is quite often, front left once in a while). At first i was suspecting a leak in the O rings of the front Air spring- however, my opinion changed recently and has confused me even further. When i am opening and closing the driver door, the deflation of the air spring is interrupted! (open- deflation stops, closed- deflation continues; this is in standstill condition).

Now i probably wouldn't bother with this phenomenon- the problem i am facing is that while i'm driving, it decides to deflate, and the front suspension becomes noisy and very bumpy till the time the compressor is able to re-inflate the air spring. i don't think this is how Mercedes would've planned out their design. Also i'm worried i'm going to kill the compressor because this inflation deflation cycle keeps happening while i'm driving.

The next question- when the air spring does have to deflate, where should the air escape from? The deflation mentioned above is quite clearly from the wheel arch area of whichever side is deflating. In my opinion, this should occur near the front of the car on the right hand side only, where the air valve is (the airmatic strut does not have a second air outlet, and extra air exhaust should occur from the solenoid block only in my opinion, and not from the strut area). :nix:

My car's been quite an experience. If it makes any difference, its an ML350 4Matic, 2006-7 build.

EDIT: I've replaced both the SAM units- front and rear (they were both faulty). All ancillary functions are now OK- but with no difference to the ride quality.

I replaced both the front struts and it made no difference. I've given up at this point and I'll just learn to live with the hard ride. The tires need to be changed soon so I might try another brand and do an alignment to see if that helps.

It sounds like your air bags might be leaking somewhere :nix: I'd hook it up to star and see if it detects a leak anywhere

further updates
 

Well I changed the rear shock on one side, and things got a little better. I haven't changed the second shock absorber, and am holding that for later.

I ran the tests on the airmatic suspension using DAS, and the following things have caught my attention:

1. My compressor isn't feeling to well. It didn't pass the 40 second inflation test.
2. All lines are OK as per the tests- no leakage anywhere.
3. ADS actuators are working fine (reading correct current readings when they are actuated)
4. The acceleration sensors seem to be at the end of the limit (2627mV

Now interestingly, the car exhibited the deflation at the time i was performing the tests, and the readings are in the last two images. The front RHS strut deflated the most (as you can see, -79mm), and the entire system pressure dropped to 4 Bar (strange?)

Now why would that happen? If there's a leak in one strut, the other struts should read a pressure of 7-8 bar; but the whole system pressure dropped. DAS isn't detecting any error however.

Do you have any idea what could be doing this? any suggestions on the way forward? I am quite hating the ride of this car.



https://cimg8.ibsrv.net/gimg/www.mbw...1cb9457181.jpg
- max is supposed to be 2.65mV

https://cimg9.ibsrv.net/gimg/www.mbw...704d1021bf.jpg


https://cimg0.ibsrv.net/gimg/www.mbw...afc2d9fc7b.jpg


https://cimg6.ibsrv.net/gimg/www.mbw...4656a75574.jpg

ESP malfunction
 

Hi. I have the exact same problem on my 2007 E280 CDI. The car is riding really hard. I had also got an ESP Malfunction error msg but that was fixed by the Dealer by replacing the Steering Angle Sensor. The error msg is now gone but the car is still riding very hard. I can feel every bump on the road.

Pls help.

As an update to my problem: I replaced the wheels/tires with winter tires and the ride improved quite a bit. I think my issue was caused by worn out tires with a hard sidewall and the ml63's firm ride. It should also be noted that the winter tires are 275 profile instead of 295. This reduces tramlining and has an improvement on ride quality. I drove my brothers c63 with performance package and the ride is back breakingly hard. It makes my ml63 seem tame by comparison.