04 X5 4.8 SELF LEVELING SUSPENSION PROBLEMS

[bmw2511]

So, now we begin to think that we're insane, swapped out the pump, relay, valve assembly, pressure sensor, level sensors etc and the thing still won't work. Pump activates for a few seconds then stops, then all the valves open at the same time and let the air out of the system! We've programmed the EHC2 unit, deleted transport mode, tried the ride height calibration, done it all over again and still no luck....

Imagine the control unit inputs and outputs as follows;

Inputs:

-CAN bus lines (communication with drivetrain systems)
-K-Bus line (communication with body systems)
-Pressure sensor signal
-Temperature sensor signal
-LHF level sensor
-RHF level sensor
-LHR level sensor
-RHR level sensor
-Level adjustment switch

-Power
-Earth

Outputs:

-CAN bus lines (communication with drivetrain systems)
-K-Bus line (communication with body systems)
-Air supply pump
-Valves for shockers
-Pressure release valves
-LED lights for level display next to switch

The car when we have everything hooked up as normal behaves as follows;

Pump operates for a few seconds, only long enough to bring pressure to about 2 BAR (needs about 5 Bar to raise car)……a few seconds later all valves open simultaneously and let all the air out of the system…….a minute later this process repeats….and again….and again, indefinitely, regardless of ignition position, switch input, or anything for that matter.

If I now pull out every single input pin from the plug at the control unit (except the power and earth supply), thus isolating this system from any input or signal it behaves in EXACTLY the same way!!

Anybody with half an idea would now suggest that the control unit is at fault. BUT, we’ve tried installing a new one, programming it and testing……..same result!!!! BMW tried the same trick…..same result again!!!

The only feasible explanation is that the software which we’ve all been feeding into this thing is at fault. Highly unlikely but still possible.

If anybody has experienced this strange problem then I would LOVE to hear from you!

[hqcdesign]

i have the same problem with suspension the compressor goes on for couple of seconds then its stop and few seconds later relice the air did you figure out the problem?

[Turbo_Bimmer]

Originally Posted by hqcdesign

i have the same problem with suspension the compressor goes on for couple of seconds then its stop and few seconds later relice the air did you figure out the problem?

Guys, take a look at the sensor links. With time, they rust in the ball socket, and don't move smoothly anymore. For a quick test, take the black plastic rod between your thumb and index, and try to pivot L-R the rod over the balls. If it moves freely, it is ok, if not, replace it or try to lube them.
My front ones were rusted solid, I had to replace them.

[Weasel]

If the light on the switch is out it most likely has either a blown fuse or bad control module... If the suspension sags it has a leak, the system doesn't just collapse on its own.

[markpfe]

Originally Posted by Weasel

If the light on the switch is out it most likely has either a blown fuse or bad control module... If the suspension sags it has a leak, the system doesn't just collapse on its own.

Is this the Control Module you are talking about?
Control unit EWS IVEWS 4.3161359145097$125.69

[WEERAB]

Best to check first thing in the morning and see which air bag is down
SWITCH ON THE IGNITION and the suspension will pump up but sometimes it will pump right to the top then you hear ssssssssssss it lowers off to the correct height
Only problem is that if this has been allowed to pump up and down for mmmmmmmmm depends on when or how far you travelled
If it has pumped up to the top 9 times out of 10 it will have knackered the level sensor that is connected to the back axle and the body of the car(just inside the rear struts)
The sensor on the front shocker or suspension is for the bi-xenon headlights and this has nothing to do with the suspension
Check the 2 back sensors for broken wires
if problem persists ill ask my autoelectrician

[markpfe]

Thank you Weerab and Weasel for your replies - I sincerely appreciate the feedback, as I'm a bit lost in all this - but like the challenge to figure this out and to resolve it.

Here are the exact symptoms (seem to be similar to Nitrogass2000):
1) Front left (only) is very low > fender is about 1 inch above tire
2) Errors message reads: Suspension is inactive
3) The Air Bag on the front left Strut is completely collapsed (see photo in previous reply)
4) Vehicle rides "hard" and bumpy
5) When I turn on the engine, no pump is activated, car does not seem to rise or change elevation.
6) Checked a series of fuses in the glove box, high-amp behind spare tire and right hand compartment in the trunk (based on instructions found in another thread) >> All fuses seemed to check fine
7) Dashboard switch to raise and lower car does not light up and does not seem to work.

Wow, that is a lot of stuff

I guess I'm trying to avoid ordering a bunch of parts that actually dont need to be replaced.

What is your best guess what steps I could take to narrow this down and troubleshoot?

Again - thank you for your insight.

[Weasel]

Link? And EWS isn't the height control, that is anti-theft... you would need EHCII.

But regaurdless you will need the strut that is collapsed. The one that rides stiff and bumpy, because it is bottomed out and the airbag on it is completely blown out by this point.

[markpfe]

yes, replacing the blown strut makes sense to me. That sounds like a good place to start with this venture.

I read in PDF document titled "X5-Self-Level___Air_Suspension-EHC.pdf" posted in a different thread that working on this air suspension system is a complicated deal - meaning: the system has to be depressurized and pressurized properly (6x) with diagnostic equipment, etc

I think I should be able to replace the Air Strut by myself, but how about these pressurizing steps etc.?

Is it really necessary to follow these steps?

I also read that my LED's on the level switch might be out, because that vehicle is in "BELT MODE"

[nitrogass2000]

GUESS WHAT PEOPLE I HAVE FOUND IT! THIS SOUNDS LIKE A VERY GOOD DEAL!

BMW Air Suspension Parts - X5 2000-2006 (3.0, 4.4, 4.8 Liter w/air suspension)

I think i will be all over this this is half price or less then BMW and LIFETIME WARRANTY!

Or does ANYONE know another company that maybe cheaper??