different air suspension pain 4.8is

[pieter4458]

I have a X5 4.8is with the famous two axle air suspension. My issue is not the normal compressor, leaking bags or control unit errors.

The problem with the car is that when parked the front drops about 10-15 mm and when start it wakes up to normal height (even if parked for 15 minutes).

I opened up the concentrator tank, checked the pipe links with soapy water, as well as the pressure regulator - no leaks. It also goes into air suspension inactive mode from time to time and then it has to be reset. No major errors on the computer when reset.

How do i fix this?

Any suggestions?

[TwinsPoppa]

If it drops at ANY time, I would start with inspecting the air strut bags and connections for leaks. How do you know its not the air struts?

Then if that checks out. I would start looking at all the other components.

[SlickGT1]

Originally Posted by pieter4458

I have a X5 4.8is with the famous two axle air suspension. My issue is not the normal compressor, leaking bags or control unit errors.

The problem with the car is that when parked the front drops about 10-15 mm and when start it wakes up to normal height (even if parked for 15 minutes).

I opened up the concentrator tank, checked the pipe links with soapy water, as well as the pressure regulator - no leaks. It also goes into air suspension inactive mode from time to time and then it has to be reset. No major errors on the computer when reset.

How do i fix this?

Any suggestions?

LOL. How exactly did this exclude the leaking bag as the problem? Mix some soap and water, put into one of those spray bottles, and spray the crap out of that bag. I bet it is leaking.

[pieter4458]

I recon that if both air bags goes down simultaneously it can not be them and suspect the lines. But it can happen that they are both bad and will test with soapy water.

[SlickGT1]

Do the same to the lines. Spray all the connections with soapy water. Watch for bubbles.

[TwinsPoppa]

Well, let's see here are the components of EHC2.

- Ride Height Sensors (x4)
- Air Suspension (air springs/struts)
- Air Supply Unit (compressor, 3 valves and a drier)
- Pressure Accumulator/Valve Unit (under vehicle)
- EHC2 Control Unit (behind the glovebox)
- Switch (ride height)

It seems like you have a leak somewhere. If not, it would definitely help to have it scanned by a GT1 and follow the test plan(s). Otherwise, could be tricky finding the root of your problem.

Meanwhile, let's see what others say and do some searches.

I wonder if the Pressure Accumulator can have a valve stuck a little open?

[pieter4458]

At one stage I suspected the o-ring on the pressure switch and replaced it, causing the accumulator to be re-filled and a computer reset to default.

After the reset the height returned to normal, but it drops as soon as the car is switched of for longer than 15 minutes. What is funny about the whole thing is that the front only dropped between 10-15mm and both sides at the same time. a Check of the links and connection points with soapy water reveals no bubbles, therefore I suspect the problem to be somewhere else. Computer, Air Bags, Control unit, Valve body or compressor can all be culprits.

The next flippen thing that happens after a few of these "get up and go" sessions is the error message of "air suspension inactive" appears, the height selector button sticks to normal and the front stops lifting - again a Reset is needed!!

Can a leaky air bag leaks to a point and then stops and both at the same time?

I hope there is an answer to this problem as I am getting frustrated with BMW and their suspension.

[TwinTurboGTR]

It sounds like a bag problem. If one bag is leaking, as the side lowers, the sensor begins leveling the other side until the bags are empty. I had to check mine twice to see which bag it was. I found a very heavy concentration of soap to water finally found the problem. WHat you need to do is raise the air height to full height, then spray the bag. If it is on the lower part of the bag, it gets folded onto its self, you won't be able to find the leak.

Give that a shot.

[TwinsPoppa]

Originally Posted by pieter4458

At one stage I suspected the o-ring on the pressure switch and replaced it, causing the accumulator to be re-filled and a computer reset to default.

After the reset the height returned to normal, but it drops as soon as the car is switched of for longer than 15 minutes. What is funny about the whole thing is that the front only dropped between 10-15mm and both sides at the same time. a Check of the links and connection points with soapy water reveals no bubbles, therefore I suspect the problem to be somewhere else. Computer, Air Bags, Control unit, Valve body or compressor can all be culprits.

The next flippen thing that happens after a few of these "get up and go" sessions is the error message of "air suspension inactive" appears, the height selector button sticks to normal and the front stops lifting - again a Reset is needed!!

Can a leaky air bag leaks to a point and then stops and both at the same time?

I hope there is a answer to this problem as I am getting frustrated with BMW and their suspension.

The SLS inactive probably comes on to save the rest of the system from being further abused.

Well, the air is coming out somewhere. If not the air suspension and connections then probably pressure accumulator or in the air supply unit as both does some venting I believe.

Off-hand, I don't know how to test those.

[pieter4458]

TwinTurboGTR, I think you can be right. When selecting to the higher level it takes longer than it used to do. I will test and report back.