Airmatic warning light

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SmileyMK

New Member
Joined
Jun 23, 2019
Messages
8
Location
Bedfordshire
Car
E350 CDI estate & 300 SL
I have a 2014 E350 CDI estate (95,000 miles) with full airmatic... And sporadically have the airmatic light come on.
Car sits level, and never drops, but some days the warning light would come on exactly the same point from leaving home (roughly 0.5 of a mile)...once the light comes on, if I press the button to raise the car, nothing happens, whereas if I press it before the light comes on, the car raises as normal.
I can hear the compressor running as I start the car, but obviously not onve the warning light comes on... and the car doesn't drop once the light comes on..it just stays level.
This happened about 12 months ago, but diagnostics didn't say what it was, garage suggested it could be the distribution valve, or possibly the compressor itself...but couldn't narrow it down.... I had nothing done, and car has behaved normally for another 12 months, until it started again about 2 weeks ago... I don't want to cause any damage to anything, but the car seems to behave normally even if the light does come on.
Any suggestions? the compressor seems to work (apart from when the light comes on)
Not related but on cold mornings it doesn't start as 'immediately' as it used to....Battery is fine and it does always start (about 5 seconds of cranking as opposed to 'immediately'... Glow plug control unit or glow plugs?
Many thanks
 
Could be compressor can't deliver enough to rise pressure up in required time limit. If your 'cold morning' means below zero C, you could have water in system, and frozen pipes are blocked/ dryer beads are wet/frozen.
 
An interesting fault, could it be a dirty or failed sensor? On this subject of Airmatic on a S212, is there somewhere a definitive description of operation of the system as in a pdf to download or be put in a "sticky"on here? I am sure there are a few well informed Indys in the know, but there are still some "horror" stories of owners being unaware of likely high costs by some dealers.
 
You may be best to book the car in for a test with a mb Indy. There are diagnostic tests within star which may identify the issue. It is not unusual as the compressor ages for its output to drop away slightly. This means that it takes longer to top up the system. When it gets so worn out the ecu will start reporting a fault on the system. A diagnostic session should confirm as you could just have a leak!
 
Your compressor is failing had the exact same issue and it was not putting out enough pressure, do you find the compressor comes on quite often and its loud? Since I had mine replaced its silent so no idea when its working but I dont get the fault message anymore, it would sometimes flash up after hard acceleration as the car tried but failed to keep the rear at a level fast enough
 
An interesting fault, could it be a dirty or failed sensor? On this subject of Airmatic on a S212, is there somewhere a definitive description of operation of the system as in a pdf to download or be put in a "sticky"on here? I am sure there are a few well informed Indys in the know, but there are still some "horror" stories of owners being unaware of likely high costs by some dealers.
 
Your compressor is failing had the exact same issue and it was not putting out enough pressure, do you find the compressor comes on quite often and its loud? Since I had mine replaced its silent so no idea when its working but I dont get the fault message anymore, it would sometimes flash up after hard acceleration as the car tried but failed to keep the rear at a level fast enough
Thankyou.... I wouldn't say it's noisy... but you can hear it outside the car... The compressor was my 'gut feeling'... I found a video online regarding changing it...so I may have go when I get a spare weekend. I did read somewhere it may need a 'star reset' after changing?... but that may not be true.
 
You may be best to book the car in for a test with a mb Indy. There are diagnostic tests within star which may identify the issue. It is not unusual as the compressor ages for its output to drop away slightly. This means that it takes longer to top up the system. When it gets so worn out the ecu will start reporting a fault on the system. A diagnostic session should confirm as you could just have a leak!
Hi... I had an independent MB look at it about a year ago when it first came on... and the star showed up nothing, despite the warning light coming on...so they suggested I left it until it came on again, which has taken a year...
 
Hi... I had an independent MB look at it about a year ago when it first came on... and the star showed up nothing, despite the warning light coming on...so they suggested I left it until it came on again, which has taken a year...
There is a serviceable filter within the pump which rarely get changed especially once cars leave the Benz network it may be worth looking at that as well, you dont say under what circumstances you get the warning is whilst on the mway or just everyday driving, when loaded etc, the fact it comes on after a startup indicates to me its unable to get to the required pressure quickly enough and that triggers a fault, however the pressure is actually reached but it takes too long. On mine once the pump was replaced a fault with an airbag came to light with the car starting to drop a few months later, I dont think its entirely coincidental as the bags degrade over time, I believe the pump may have been working overtime for a while replacing lost air within the system caused by a slow leak and this is what ultimately caused it to fail/wear out.
I got myself one of these and had my local garage replace the parts which I was then able to configure and calibrate with the built in menus, specialist wanted £900.00 to replace the parts and "code" ( read press a button on a reader) I got it done for £300.00 less with Arnott parts
 
Well a indy with Star should be abe to test the airmatic pump,there is a test where it empties the little air tank near the pump and then asks the pump to fill it,the pump has a certain amount of time to do this,failure to do this puts up the warning message,the cost of a new pump fitted is not huge and the indy will check to make certain there is no leak around the small tank area,the fact that you get the fault light at around the same time into a drive suggests it is the pump.
 
There is a serviceable filter within the pump which rarely get changed especially once cars leave the Benz network it may be worth looking at that as well, you dont say under what circumstances you get the warning is whilst on the mway or just everyday driving, when loaded etc, the fact it comes on after a startup indicates to me its unable to get to the required pressure quickly enough and that triggers a fault, however the pressure is actually reached but it takes too long. On mine once the pump was replaced a fault with an airbag came to light with the car starting to drop a few months later, I dont think its entirely coincidental as the bags degrade over time, I believe the pump may have been working overtime for a while replacing lost air within the system caused by a slow leak and this is what ultimately caused it to fail/wear out.
I got myself one of these and had my local garage replace the parts which I was then able to configure and calibrate with the built in menus, specialist wanted £900.00 to replace the parts and "code" ( read press a button on a reader) I got it done for £300.00 less with Arnott parts
Hi... the warning light comes on during normal everyday driving... and comes on pretty much after the same distance (if it is going to come on...which it doesn't everyday)...about 0.5 miles away from home. Hopefully it is just the compressor, as the car will happily sit overnight without dropping...
 
Well a indy with Star should be abe to test the airmatic pump,there is a test where it empties the little air tank near the pump and then asks the pump to fill it,the pump has a certain amount of time to do this,failure to do this puts up the warning message,the cost of a new pump fitted is not huge and the indy will check to make certain there is no leak around the small tank area,the fact that you get the fault light at around the same time into a drive suggests it is the pump.
I can do the same test with the tester I have, the new pump was £560 fitted as I did not have my gizmo then I had to use an indy not a mistake I will repeat now I have this tester which allows me to do exactly what they can
 
Well we are big fans of the icarsoft diagnostics on here,and yes you can change the pump as a DIY job as many MB's have the pump behind the front bumper passenger side and the metal sphere that holds the air is right next to it on the S class, so checking for leaks is quiet easy,as you must have found out now,the pump itself does not pump up the bags,it just gets told to top up the sphere when air is used by the suspension,most indies will not fit very cheap pumps ,when I had mine done the pimp was £375 plus they found a leak near the sphere and repaired that,so as bills go for a MB £560 ain't too bad if you say it quickly.
 
mines in the rear N/S as is the air tank on the E class estate at least on mine which is full airmatic its quite a chunky oval shaped device, you could go bush mechanic support the car and crack open a connection to let the air out its high pressure but low volume.
 
An update.... I'm going to try to get an independent to do a check... the light does still come on pretty much every day now, roughly the same 'distance' from home (about 1-2 mins).... so I'd resigned myself it was probably the compressor (ordered yesterday).... but then this morning, the car had lost air at the rear, (first time this has happened)... yes, it pumps itself up once engine running...

But now I suspect there must be a leak somewhere too?...
 
Find the leak before you do the pump, it could be the actual pump itself but more likely an airbag has a pinhole
 
Find the leak before you do the pump, it could be the actual pump itself but more likely an airbag has a pinhole

This is certainly a weak point on 212's. Anecdotally, I'm told they tend to fail "at around the 10 year mark". One (or maybe both) of mine started playing up on 10 years/70-odd thousand so I had them replaced last year. In my case the clue was overnight sagging
and the odd warning when I was trying to set off before it had fully risen.

The bag and struts on my previous Airmatic E, a 211, lasted 12 years/145k. But he compressor gave up in the 120's.
 
Had the same problem myself, every trip within short distance amber malfunction came up on dash. As car had no obvious problems, e.g. left same height as rear etc., just cancelled the light using ok button. Before Christmas was not a convenient time in case of cost!
Spoke to local indy at end of Jan and booked in soon after. Found to be some sensors out of cal range, so they were replaced and system checked over for leaks, correct operation etc.
 
booked in on Monday... will report back
 

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