Max.H

Started to ge the malfunction light on dash with arrow up. then right rear slams one day. drive over hump and it fills back up with air and its fine for a few days. Raises and lowers fine. Still light on dash.

I swapped airmatic pump. but light does not go away and right rear slammed again.

Could it be the rear height sensor or air spring?

How come I can put a jack under the car and raise it up and after a little while with car on it fills up with air and goes up and down like normal?

What can it be? I don't have star yet so Im stuck doing this archaic way.

Any help would be appreciated.

bbirdwell

First thing I would check (without a diagnostic system, of course) is the connector at the air spring. Pull it, hit it with contact cleaner, mate/demate a few times, then reinstall.

Still, could also be the air spring going bad so do not discount that path.

FWIW, I installed Arnotts on all four corners simultaneously last January. A couple of weeks ago dash shows Airmatic malfunction, left front corner was low, then raised, malfunction light comes and goes. Ran diagnostics, results showed stored fault of an open circuit to the fill valve in the left front air spring. Pulled connector, cleaned contacts, reinstalled, two weeks and counting with no malfunction light.

If only one corner is dropping, it's not the compressor. It's a leaking air spring, bad valve in the air spring, leaking pneumatic line, or a bad electrical connection (open or shorted). The diagnostic system greatly simplifies the process.

Max.H

Both rear is slammed now . Could it be rear height level sensor? I need to jack it up and let it fill with air tomorrow take it the dealer and have them run the codes. But, its a ways. Not sure if the car will make it or not.

Where are the connectors to the airsprings located? I wil hit it with contact cleaner and do what you reccomend. It's worth a try.

I figured the air pump is 10 years old so it was worth replacing anyways. But. the light is still on the dash.

bbirdwell

Connectors are on the air bags; you can get to them by removing the rear wheels. Plumbing of pneumatic system attached; the air valves on the rear bags should prevent loss of air through the plumbing if there was a leak in one of the lines. It pays to spray soapy water on all of the fittings and to inspect the T-junction under the rear subframe in the middle of the car.

Both of my air springs began leaking around the 100,000 mile mark; one badly, one not so badly. I replaced all four corners with Arnotts.

Max.H

Me thinks the rear air springs are leaking. Will see tomorrow. This christmas I need a star or at least that icarsoft.

StarvingArtist

Sounds like sticky linkage to the rear level sensor.

Max.H

Ive been asking where it's located and what that thing looks like. How do you check it?

knowbenz

It mounts to the rear sway bar, to the left of the diff and above. sounds like leaking springs

Max.H

Put a jack under car last night started it up. Raised and lowered a few times. Both rears filled up with air. Car sits normal. Does not leak even after a week of sitting. Done this a few times

Gonna try to check the height sensor arm today after work.

I'm ready to buy some new arnots. Just wanna know before I get em.

Max.H

Got under the car. the level sensor is in the middle of the car next to the diff? There is no way to get to the plug without doing some serious work. Or am I missing something?

I dont have a star and the dealer is too far away to get the car down there without risking the car dropping on the way there. SOB! LoL

I think im going to bite the bullet and buy 2 arnots. What else can cause this issue? I hate to swap the air springs and its something else?

I sprayed soapy water no leaks around the fittings to the air springs or at the junction point in the middle of the car.

StarvingArtist

Did you spray some oil on the sensor link? Mine did weird stuff when the link got sticky. My next guess would be the valve block because it's happening evenly. Both springs didn't develop the same problem at the same time. Something is happening upstream. Don't know anything about the valve block, but I think it would throw a code.

Max.H

Just don't want to spray wd40 next to the sensor itself and cause an issue? Not much of the sensor and arm are exposed from under the car So it's kinda hard to see behind the axle. I will try it now.

It's just weird, Im ready to pull the trigger on a pair of arnots. But, If it's something else also. It's gonna suck. Need to know everything I need to buy. I wanna do the job once.

Edit. A buddy is bringing over a launch scanner next week, he says works with BMW and MB cars. So, we shall see.

StarvingArtist

The sensor survives a lot worse than wd40, if that hurts it, the seals are shot anyway.

knowbenz

The electrical connector on the air bag is for the level control valve. It is normally closed when car is off. You can disconnect the air line and it won't drop down on a properly operating system. Replace the bags and be done with it. Also, one leaking will pull down both sides, one more than the other if only one leaking.

Max.H

The rear height level sensor looks like a total PITA to swap. You would need to drop the axle on the passenger side. Things like this seem good to change on a 10 year old car. What do you guys think?

Max.H

Good point.

Max.H

Got the codes:

5350 airmatic pressure release valve: Open circuit
5500 critical vehicle level at front axle
5501 critical vehicle level at rear
5502 Level calibration was not sucessfully carried out

Says nothing about any of the air springs. Does anyone know the codes you get when the air springs (air bags) have a leak? That would be greatly appreciated.

Ive read that there is a known wiring issue on one of the plugs on the airmatic pump. That it rubs against the plastic fender liner and can wear out the or break the wire causing an issue. But, not sure if that applies to me.

Going to get under the car and check the wiring. "It says open circuit" So, I'm guessing that means one of the wires is broken at the plug.

knowbenz

If yo have a leaking bag or strut you will get critical vehicle level codes. If it takes long time to fill up you can get pressure line leak codes. if pressure relief valve is open circuit then it won't dump pressure, meaning it can stay in an elevated position. level calibration code means exactly as it reads. when was the last time codes were cleared? These codes could be from the past. clear all codes and see if any come back.

Again, when the car is off the level control valve remains closed, the air will only leak out of the bag. You can take air line off on a functioning system and it won't drop when parked unless the bag is leaking. I really think you are going in circles when you don't have to. The bags are cheap enough and easy enough to change that you should just do it and get it over with. Unless you have a lot of free time

Hulk

^^^^^^ this

Max.H

Then why does the car sit at normal height for days weeks without dropping? If the bags were leaking. That is the part that I don't get. If I knew it was bags they would be on the car already. If it's not the bags rather not waste 700 bucks on something that isn't broke. I just need to confirm before buying the parts I need.

So, that means I need at least 1 front and 1 rear air spring. Because it said front and rear critical. Couldn't that be from when the rear slammed and threw front and rear height off? I wish the gdam thing would say leaking front air spring left or right rear whatever. Or something more concrete.

Has anyone experienced this?

knowbenz

I have had multiple vehicles come in with a complaint of sitting low. There have been times we park the cars for days and it doesn't lower, move the car to a different parking spot and it lowers within minutes. You could have a tiny leak where the airbag seals on the lower part, the bag then comes down the base and rolls over to go up like in this pic


the rest of the bag that is tight up against that base which can aid in sealing it. You can hit a bump, park at a different angle, anything that moves the bag, and you could have the air leak out the next time you park it.

Depending on how low the car goes when it does leak, it could go down enough to give you critical level codes for the front as well. Also, if you haven't cleared all the codes for a number of months or years then there is no telling when that code was set.

And again, you can take the air line off of the strut or bag when the car is off and it will not lower unless there is a leak in the strut.

But if you want, just keep driving the car until it gets worse

Max.H

Good points, makes sense. I will need to check the open circuit issue on the pressure release valve first.

What codes does the car throw when airbags are leaking? Does it say which side too?

The codes were cleared by Mercedes dealer last oil change. That was like 8 months ago.



Car is not being driven, it is not a daily driver anymore either. Just driven around the block to check this issue. So, that takes that out of the equation.

Max.H

UPDATE: checked the wiring going to the pump and sure enough the wire was bent almost in half. Cut the wires back and soldered with heat shrink. CODE 5350 airmatic pressure release valve open circuit. Went away.

Now onto the bad. The airmatic fault code on the dash still lit up. ONLY code after wiring repair is 5502 airmatic calibration not successful.

I'm Ordering a set of rear arnots anways. But, Anyone know what 5502 means?

knowbenz

it means the calibration was not successful. Make sure the level sensor values are within spec then go through the calibration process to lock in the specified ride height.

Max.H

We looked at the voltage of each level sensor they looked good. But, car was not on level surface a the time.

What is the calibration process? Can it cause any issues?

Also checked the pressure of the airmatic system. I think it was 14.8 bars.