AirMatic Issues and Troubleshooting
I've recently acquired a 2007 Mercedes GL320 Diesel and it's a fantastic leviathan of a Vehicle (My Kids called it the "Panzer" because it's a Tank)
I've had some issues with the "Compressor Cooling Down" Error....I figured based on past experiences with Land Rovers etc that the Air Suspension Compressor was dying... Bought a replacement and fitted as well as getting the better Hella Genuine Mercedes Relay and the issues continue.
The Car doesn't lose height at all overnight, so I believe that means that the Valve Block and Springs themselves should be ok. The Intake Hose to the Compressor was damaged at the End so I chopped it down and checked rest of the hose was ok....haven't replaced the Filter as yet.
Should I be looking at potential leaks towards the Air Tank in the rear? I was hoping for some potential knowledgeable hints and tips as to where to look next.
I find if I keep the car at Off Road Height 1 it's fine, until I go above 110km or so for a while and then it goes down the the Normal Height and very shortly the car feels like there is no suspension at all and my back jars nastily...
I press the height adjustment up and at that point I get the Compressor Cooling Down Message.
I've removed the 40A Fuse to disable Air Suspension Compressor for now and see how it goes without that before I can get troubleshooting on the weekend.
Did around 30 Miles/50km today with the 40A Fuse Removed. Car didn't report any issues until I started up on an Uphill Climb and it then stated "Malfunction" with the Height Symbol in the Centre Display Behind Steering Wheel.
When I got home Car seemed to be at roughly the same gap between Rear Wheels/Front Wheels and Top of Wheel Arch etc... so didn't appear to have any leaks in the system.
I will pull out my MaxiDAS DS808 Code Scanner Tomorrow to see if there is a sensor issue or similar.
your code reader will tell you where to look - in this case the compressor is shot; but why?
most often due to leaky airbags. Since you say your rear sags that would indicate a leak in the rear bags.
see if you can fully raise the car and spray them down with soapy water or leak detector. It’ll be obvious.
if not, rear airbags are fairly cheap and take about 15 mins a side to replace.
your code reader will tell you where to look - in this case the compressor is shot; but why?
most often due to leaky airbags. Since you say your rear sags that would indicate a leak in the rear bags.
see if you can fully raise the car and spray them down with soapy water or leak detector. It’ll be obvious.
if not, rear airbags are fairly cheap and take about 15 mins a side to replace.
...Should I be looking at potential leaks towards the Air Tank in the rear?....
I find if I keep the car at Off Road Height 1 it's fine, until I go above 110km or so for a while and then it goes down the the Normal Height and very shortly the car feels like there is no suspension at all and my back jars nastily...
how old are your rear bags?
I've sprayed the Leak Check Spray around the Front Struts Connections (No Bubbles) and at the Rear Air Reservoir Tank Inlets and Join between the Tanks (No Bubbles).
I've read the Codes with the Code Scanner and I get
Error Code: 5503 - Recovery Time during filling of central reservoir too long
Error Code: 5111 - Check the Component 'B24/4' (Right Front Body Acceleration Sensor)
Those are exactly what the MaxiDas DS808 give me as descriptions.
I've cleared these codes now and they haven't come back as yet... However I will take the car for another drive and see how I go.
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1) B24/4 Error re-occurs.
I've since discovered the diagnostic menu in the MaxiDas and was able to test each pneumatic valve etc... What I'm left with is the following.
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 leak tight.
This pretty much leaves me to believe I either
a) Have a Faulty Valve Block or more likely
b) There is an issue/leak with the Right Front Strut.
I'll have a look at the lines etc from the Valve Block to this particular strut to make sure they aren't loose etc but looks like I might have found my issue.
All of the other Tests of Components were fine/around the same values.
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Interestingly this side seems fairly generic/original where-as the Left Hand Side looks to be Arnott Strut..
looks like the scan tool directed you to look at the actual culprit, with the limitation that it cannot test each individual air bag -only the line from the compressor to the block, or the line from the block to the bag (which would include the bag).
Just thinking ahead, your compressor has been working hard to fill the atmosphere through the leaky bag. do you have an option to test the compressor output? The test threshold is 16 bar within 40 seconds. a new compressor should reach 16 bar within 1-2 seconds.







