2012 GL450 Airmatic Issue
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Newbie
Joined: Sep 2020
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From: VA
GL450
2012 GL450 Airmatic Issue
Hi, Everyone, I am new here. Found out the forum while searching for help.
My 2012 GL450 rear suspension were lowering intermittently for some time and left side went down completely one day, while it was parking in garage for a week or so, the other rear air bag busted as well.( the first failed air bag was with small leak, but the second one was tore broken)
I replaced the two rear air suspensions with Arnott OEM, but both didn't come up. I tried to use raise car function but only got the front up to the highest level, the rear end was still at the lowest level with no air at all pumped in the suspension. then I noticed the front refused to lower down even I pressed lower the vehicle button.
Then I bought the Autel tester to run the diagnostics.
VIN： 4JGBF7BE0CA801644
With car being jacked up, I have run the pneumatic test with following results
1.Pneumatic test of component A9/1 (Airmatic compressor unit):Component A9/1 functions properly.
2.Pneumatic test of component A9/1y1 (AIRmatic pressure release valve):Component A9/1y1 (AIRmatic pressure release valve) functions properly.
3.Pneumatic test of component Y36/6Y1 (Left front level control valve):
Component Y36/6Y1 (Left front level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
4. Pneumatic test of component Y36/6Y2 (Right front level control valve):
Component Y36/6Y2 (Right front level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
5. Pneumatic test of component Y36/6Y3 (Left rear level control valve):
Component Y36/6Y3 (Left rear level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
6. Pneumatic test of component Y36/6Y4 (Right rear level control valve):
Component Y36/6Y4 (Right rear level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
7. Pneumatic test of component Y36/6Y5 (AIRmatic central reservoir charge valve):Component Y36/6Y5 (AIRmatic central reservoir charge valve) functions properly.
8. Leakage test between compressor and valve block: The line between the compressor and valve block does not leak.
9. Leakage test between valve block and suspension struts: Not able to test as the car was still jacked up
10. Leakage test between valve block and central reservoir: No gross leak was detected.Check system for fine leaks.
I have also tested the compressor and it worked fine with 200+PSI generated
So all 4 level control valve had issues but the reservoir charge valve works fine. I guess I can rule out the power issue and at least one valve works, Was it because the car was jacked up and prevented the level sensor to control the valve? or I should replace the whole level control valve assembly?
Any advice is much appreciated.
My 2012 GL450 rear suspension were lowering intermittently for some time and left side went down completely one day, while it was parking in garage for a week or so, the other rear air bag busted as well.( the first failed air bag was with small leak, but the second one was tore broken)
I replaced the two rear air suspensions with Arnott OEM, but both didn't come up. I tried to use raise car function but only got the front up to the highest level, the rear end was still at the lowest level with no air at all pumped in the suspension. then I noticed the front refused to lower down even I pressed lower the vehicle button.
Then I bought the Autel tester to run the diagnostics.
VIN： 4JGBF7BE0CA801644
With car being jacked up, I have run the pneumatic test with following results
1.Pneumatic test of component A9/1 (Airmatic compressor unit):Component A9/1 functions properly.
2.Pneumatic test of component A9/1y1 (AIRmatic pressure release valve):Component A9/1y1 (AIRmatic pressure release valve) functions properly.
3.Pneumatic test of component Y36/6Y1 (Left front level control valve):
Component Y36/6Y1 (Left front level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
4. Pneumatic test of component Y36/6Y2 (Right front level control valve):
Component Y36/6Y2 (Right front level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
5. Pneumatic test of component Y36/6Y3 (Left rear level control valve):
Component Y36/6Y3 (Left rear level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
6. Pneumatic test of component Y36/6Y4 (Right rear level control valve):
Component Y36/6Y4 (Right rear level control valve) is not operating properly or the line between the valve block and the suspension strut is not leaktight.
7. Pneumatic test of component Y36/6Y5 (AIRmatic central reservoir charge valve):Component Y36/6Y5 (AIRmatic central reservoir charge valve) functions properly.
8. Leakage test between compressor and valve block: The line between the compressor and valve block does not leak.
9. Leakage test between valve block and suspension struts: Not able to test as the car was still jacked up
10. Leakage test between valve block and central reservoir: No gross leak was detected.Check system for fine leaks.
I have also tested the compressor and it worked fine with 200+PSI generated
So all 4 level control valve had issues but the reservoir charge valve works fine. I guess I can rule out the power issue and at least one valve works, Was it because the car was jacked up and prevented the level sensor to control the valve? or I should replace the whole level control valve assembly?
Any advice is much appreciated.
Last edited by Patrickz; Sep 19, 2020 at 12:43 AM.
Member
Joined: Nov 2005
Posts: 165
Likes: 27
From: Buford, Ga
2023 EQE AMG
I think you only have two options take valve block off and attempt to service it? Or replace it depending on mileage. I tend to try and service things before replacing things. The block is easy to get to and remove its on passenger front wheel fender liner.. jack up truck remove wheel remove fender liner.. you maybe able to keep wheel on but will have less working space.
MBWorld Fanatic!
Joined: Jan 2010
Posts: 3,116
Likes: 782
NGL450 w/EORP, S550
Test 9 is actually the same as test 3 - there's no valve on the bag side.
So if the valve block isn't functioning properly you'll have what seems to be leaks in the four branches from the valve block to each bag.
Can Autel also inflate each corner? If you're able to do that then your valve block should be ok.
Can your Autel also do level sensor readouts? That may yield a clue as to which axle sensor may be reading wrong. You can check that with the car lowered to a "normal" ride height and comparing sensor values. With some gentle rocking the values should fluctuate as well.
So if the valve block isn't functioning properly you'll have what seems to be leaks in the four branches from the valve block to each bag.
Can Autel also inflate each corner? If you're able to do that then your valve block should be ok.
Can your Autel also do level sensor readouts? That may yield a clue as to which axle sensor may be reading wrong. You can check that with the car lowered to a "normal" ride height and comparing sensor values. With some gentle rocking the values should fluctuate as well.
Junior Member
Joined: Feb 2016
Posts: 33
Likes: 2
From: AZ
2012 CLS550 Launch Edition, 2011 GL550
I would not recommend Arnott to anyone. They claim they are compatible with the GL class but the spring specs say 100 psi max. The GL with 0 load is 113 psi, with trailer 145 psi, as shown from Shop scanner. As you can see the minimum load on the air spring is already over the MAX psi of the spring, this also means Arnott should be telling people they cannot use this part if the vehicle has a tow package. My first one blew while towing 400 miles from home. Arnott insisted it was just a defect. The 2nd one blew 650 miles from home. Now I am done!! Its a complete misrepresentation of the product. I replaced all 4 corners with this brand only to find out how inferior it is. I made a huge mistake!! I hope this helps someone else not make the same mistake. I have done complete end to end component tests of the suspension system in my vehicle, this product is just not as advertised. I urge anyone considering this product to do extensive research before deciding what to use for this. We cannot even trust American made products anymore.
