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Hello. My wife's 2012 GL450 air suspension is stuck on the up position. When pressing the button to lower, the light would keep on blinking but the suspension would not lower to the normal position.
I check the the two 40A orange fueses and the green relay but all 3 were in good shape (I did have these 3 replaced about a year ago when our mechanic replaced the air compressor). I had my mechanic take a look at the wiring on the air compressor but he did not see any wires that were broke or loose.
I forgot to have him check the valve when he had the right wheel off. Do you think that's the next place to check is to see if the valve is stuck or clogged on the air compressor? If so, do you know where the valve is on the air compressor? Currently the air compressor is an Arnott unit. I've attached a pic with a red circle? Just seeing if that is the valve I need to check?
Besides the valve, is there anything else I should check? Thanks!
Stuck or binding level sensor.
Look in the wheel well for a plastic rod hooked to an arm.
If these are unplugged, broken, binding or bent the system gets erroneous level inputs and does weird things.
Lowering is not a function of the compressor, but does involve the valve block to let air out. But the signal to lower comes from the level sensors so start there.
Adding to what Max said... you can easily pop the level sensor arms off and play with the mechanisms to see if they're not moving like they should. Clean the moving parts (ball/socket/etc) and grease.
Thanks guys for the help. I think I'm going to check it out myself first. I'm not that mechanically inclined (can only due the basic oil change, filter changes and swap winter to summer wheels) and so can you let me know if the attached pics is the correct level sensor that I'm suppose to look for. Also is this on the right side (passenger - N.A. cars) front wheel well close to the compressor? Thanks again!
There's a level sensor at each wheel. Look over the top of the wheel to the inside - relatively in the middle of the wheel well (front to back, that is).
Thanks DennisG01. I think I got it now. I should look at all 4 leveling sensors to see if there is any binding, wires cut and play with the arm to see if it's moving freely. In my notes for this vehicle, I do see in 2018 my previous mechanic recommend replacing all 4 leveling links. I think a that time one side was lower than the other. I did purchase all 4 leveling links at the dealer and the mechanic replaced them.
Just want to make sure is the attached photo (taken from the internet) what I'm suppose to look for the leveling sensor (which is connected to bottome of the leveling links)?
If that is the correct sensor, I should check all 4 leveling sensors to make sure none of them are damage or having binding issues?
Lastly, if one is not functioning correctly, it can cause the entire airmatic to raise all the way up on all 4 corners? Just checking if that is the case.
Yup. That long, black, plastic arm can be twisted/popped off to check if the short, lever arm moves freely. The ball/socket that I mentioned is at each end of the long arm. These are what the computer uses to know where each corner of the car are. I'm not sure exactly what the "algorithm" is that the computer uses, but it's safe to say that if one is giving erroneous info, then the computer is confused.
Whether this is the issue remaines to be seen. But it's a possibility... and free to check! Do you have a scanner? Even some of the inexpensive ones can read real time level sensor data. I have an iCarsoft MB II and that does it.
Thanks again Max Blast and DennisG01. Much appreciated.
I do remember borrowing my friend's iCarsoft smaller handheld scan tool a few years ago to diagnose my R230's hardtop issue.
Would the iCarsoft entery level scan tool for Mercedes tell me the exact sensor that has an error code if it's the sensor? Or will it only give me a generic code that it could be 1 of the 4 sensors that has an issues?
If it does provide the exact sensor (ie. Rear Left sensor) than I might just buy one as it will be usefull for my X164, R230 and W212. Thanks!
I just started having this issue. New compressor. New bags. New sensors. New relay. New fuse.
The vehicle raises a little bit each time the car is started until, after several starts/trips, it is raised all the way. Pressing the raise/lower button will raise the vehicle, but not lower it; and ultimately results in an airmatic 'visit workshop' error - the vehicle remains at max height.
Driving at highway speeds has no effect on ride height (it should automatically lower at around 35mph).
I can empty the bags manually (unscrew the 10mm nut on each bag) only to have the process start over again.
I used to hear regular puffs or 'pressure releases' with my old compressor (like a semi truck's air brakes). The new one makes no such noise. So somewhere the pressure is not being released and just building up during each start.
The only other thing to inspect/replace is the valve block, but other threads indicate that this did not resolve the issue either.
Last edited by Miguk_Saram; 09-30-2021 at 05:20 PM.
Hello there
This is not exactly the same as above, but kinda..
I have also changed to Arnott in the rear of my car (GL350 Bluetec 2011) and all was well til...! I went and changed my tires!!! I went to Big O Tires to buy/order OEM tires for my GL
Once they got them, I asked them to do an alignment (of course), once back to Big O Tires (Elko NV), I meet with the guy who told me that they could not do an alignment, due to something was rusty.. hmm (I never seen any rust on/under my car)
Well, ok I got my car
It felt a little weird, pulling slightly to the right and so.. Some day back to Big O Tires and mentioned this: "Oh no, we never did any alignment so it cant be from there, sometimes new tires can do this"..
Still pulling to right, cant let go of the steering wheel without the car heading out from the road Later I also notice that the Traction Control light flashes when taking curves or the brakes reacting as it is icy outside !!
Ok, so now I just changed my rear shocks for the Arnott ones and scanned the vehicle with a scanner..
The scanner shows this about the levels: Front Left -21mm Front Right -39mm Rear Left -72mm Rear Right -32mm
How do I adjust the levels to the same/right ones??
Please, anyone knows how??
Thank You
Glenn St George UT
I just started having this issue. New compressor. New bags. New sensors. New relay. New fuse.
The vehicle raises a little bit each time the car is started until, after several starts/trips, it is raised all the way. Pressing the raise/lower button will raise the vehicle, but not lower it; and ultimately results in an airmatic 'visit workshop' error - the vehicle remains at max height.
Driving at highway speeds has no effect on ride height (it should automatically lower at around 35mph).
I can empty the bags manually (unscrew the 10mm nut on each bag) only to have the process start over again.
I used to hear regular puffs or 'pressure releases' with my old compressor (like a semi truck's air brakes). The new one makes no such noise. So somewhere the pressure is not being released and just building up during each start.
The only other thing to inspect/replace is the valve block, but other threads indicate that this did not resolve the issue either.
What about the valve block? Have you troubleshoot it?
I would suspect it as you're not getting any air to release from the airmatic system. Not sure if you can test the valves individually, may need to dismount it from the car unless you can interrogate it with Xentry or another tool.
And updates on this issue? I’m interested to see what the issue was as my friends E63 is doing the same thing. I suspect it’s the valve manifold block that’s not releasing the air. All his level sensors seem fine.
Exact same problem.....wish i have found a solution in this thread ( I wonder why that electrical plug on the compressor is circled in the first picture - i have read that we have to make sure the connector is properly plugged, sometimes it is not.
One suggestion I have not seen on this thread: try disconnecting the joint on both sensor arms and extending the arms upward to trick the sensor into releasing the air. (sensor arm down means car is sitting below level = signal to raise; sensor arm up means car is sitting above level = signal to lower).
If there is a change in height, then your sensors may just need to be calibrated, if there is NO change in height, then either your sensors, or the Valve Block may be the issue.
Caution: you will be working UNDER your vehicle, so be sure to lift and support it adequately. You will need sufficient clearance below the vehicle to allow for the height settling all the way down to just the shocks (6" to 8" off the ground). For your own safety, do NOT work/rely on the vehicle being perma-raised to get under it without adequate support (jack stands).
Last edited by Miguk_Saram; 06-28-2022 at 06:36 PM.
One suggestion I have not seen on this thread: try disconnecting the joint on both sensor arms and extended the arms upward to trick the sensor into releasing the air. (sensor arm down means car is is sitting below level = signal to raise; sensor arm up means car is sitting above level = signal to lower).
If there is a change in height, then your sensors may just need to be calibrated, if there is NO change in height, then either your sensors, or the Valve Block may be the issue.
Caution: you will be working UNDER your vehicle, so be sure to lift and support it adequately. You will need sufficient clearance below the vehicle to allow for the height settling all the way down to just the shocks (6" to 8" off the ground). For your own safety, do NOT work/rely on the vehicle being perma-raised to get under it without adequate support (jack stands).
This worked exactly as you suggested. I want to say while the car/engine was ON, playing with the disconnected sensor did nothing. However as soon as I shut of the engine, I was able to manually lower each side - I lowered it a little too much on purpose, so when it starts out it will go to its operating height.
All good now.
I haven't gotten to it yet, and may not for a while. I will, however, post back when I do find a solution.
Just noticed I never came back to update on this.
Simple: I got tired of dealing with the airmatic, so I converted to coils.
I had to have an indy install them though. When I tried to DIY, I could not get enough compression in the coils to install safely with the tools I had available.
Thanks guys for the help. I think I'm going to check it out myself first. I'm not that mechanically inclined (can only due the basic oil change, filter changes and swap winter to summer wheels) and so can you let me know if the attached pics is the correct level sensor that I'm suppose to look for. Also is this on the right side (passenger - N.A. cars) front wheel well close to the compressor? Thanks again!
note that if you replace this unit it will need to be calibrated to your car. or it will sit lopsided.
Simple: I got tired of dealing with the airmatic, so I converted to coils.
I had to have an indy install them though. When I tried to DIY, I could not get enough compression in the coils to install safely with the tools I had available.
I'm kicking around going to coils. When I asked about error codes, Suncore says "the vehicle will need to be taken to a shop that has a Mercedes scanner to disable the warning message from inside the cars computer". How did you do this? Are you glad you went to coils?
07-25-2021, 10:33 PM
Do you have a scanner? Even some of the inexpensive ones can read real time level sensor data. I have an iCarsoft MB II and that does it.
Uneven levels of the airbags
( I wonder why that electrical plug on the compressor is circled in the first picture - i have read that we have to make sure the connector is properly plugged, sometimes it is not.
