never ending 4.8is Air Suspension Nightmare

[bmwtoronto]

I have a 2005 x5 4.8is and have had endless trouble with my air suspension. I have replaced all 4 of the air bags in addition to the compressor. twenty minutes after leaving the dealership the "air suspenion inactive" notification lights up on the dashboard. I've now spent $5000 in hopes of finally repairing this air suspension issue but have had no luck. The first time the air supension failed, I was stopped at a red light. out of nowhere the front air suspenion bags popped like a ballon! My car was literally 1 inch off the ground. I replaced the 2 fronts, but then a few weeks later the same thing happened to the rear air suspension bags. At the moment my dashboard still gives me the air suspension inactive notification, but the ride hieght is somewhat normal. that being said, when i leave for work in the morning my car is usually lobsided like the leaning tower of pesa. has anyone had this problem/ any suggestions on how this problem can be solved?

[Pisendar]

Excuse me, is air bags and struts basically the same things?!

[kmagnuss]

Originally Posted by Pisendar

Excuse me, is air bags and struts basically the same things?!

No. Air bags are like springs, whereas struts are like shocks.

Sorry about your luck man... You obviously have a leak somewhere still. Maybe it's in the valve block. Unfortunately BMW mechanics seem to be just as oblivious to repairing air suspension as Land Rover mechanics, and you may need to do some diagnosing on your own.

I would get a spray bottle of soapy water and spray every bag (on each different height setting), every line, the compressor, and the valve block until you find the bubbling (the leak). Also keep listening for a hiss. Typically you won't be able to hear the hiss but sometimes it's a big enough leak that you will.

Good luck.

[Pisendar]

after replacing struts and air compressor everything was fine!!!

[kmagnuss]

Fonzie says, "AAAAAAAY!"

[jst2878]

Check the air lines for leaks with soapy water

[esntrk1]

I'm new to the forums. Just bought an '05 X5 4.8is with 98k and it had the suspension problem. I bought the Bentley service manual and studied the entire system. I understand it quite a bit. It's a pretty clever system but because it has so many fail points, it generally is a pain. Still, when it works correctly it's soooo worth it.

Anyway, if all four of your bags suddenly deflate then it's obviously not a slow leak. It's a control issue. I would go directly for the controller that is mounted behind the glove box (4.8is). The controller accepts inputs from the sensors. The sensors have no clue how much air is in the bags. The sensor has magnet that moves through a magnetic field. When the vehicle raises and lowers, the magnet moves up and down. This changes the voltage that is sent to the controller.

That's why the leveling program is needed. The tech will level the car by measuring the distance from the floor to the fender well. When all distances are equal, the sensor voltages are stored in the ECM. So when you tell the vehicle to level, the controller tells the valve unit to add or remove air from each bag until the sensor voltages are the same as stored in the ECM. The valve unit and pressure accumulator are mounted underneath the vehicle on the passenger side. IMO, the valve unit is overlooked quit a bit. It's really the operator for the entire system. The controller makes the decisions, the valve unit acts on them. If either one fails and then all fail. The compressor only kicks in when there is not enough air in the pressure accumulator. The pressure accumulator stores air so the compressor doesn't have to work as hard. It's nice but if your'e leaking air faster than the compressor can pump then eventually the compressor will burn out; it's just not designed to run for extended periods of time.

Remember, if you have having problems with leveling or intermittent leaks then address it right away or limit use of the vehicle. If you drive it with the problem then that will overwork the compressor and you run the risk of burning it out. Have a look at the valve unit. Make sure that those air line connectors at the top of the strut are not loose (you have to look inside the fender well for the yellow air supply line). Use a 2x4 or similar piece of wood to measure the height at each fender well. Mark the level position on the wood and check it regularly at all four corners.

I hope this helps. I'm not a technician but I did grow up working on cars. Now I just work behind a desk. If any of my info is incorrect, I ask that some of the senior members (weasle) correct me.

I was able to get my air supsension fixed but the information I found here on the forums along with the manual and a pdf document of how the system works. I instructed the tech on what to look for and how to go about troubleshooting. We got it right the first time.

[AZX54.4]

I have replaced both front air struts. Sometimes I find the right side of the X is 3/4 inch lower than the drivers side. This is somewhat intermittent. I have checked for leaks and have not found any. I listen for my compressor and it is not on for long periods of time. The air suspension hunt....

[esntrk1]

Replace the sensor on that side that is 3/4 lower. It's unlikely that the sensor is bad but it is a relatively inexpensive item and you can rule it right away. You may even be able to replace yourself.

[mywidebody02]

or you can swap sensors left to right and see if it follows which will prove it is the sensor.