E53 Electronic Height Control

[2mbb]

Hi: I'm trying to get some more information to help trouble shoot an issue I'm having with the electronic height control (EHC) on my 2001 X5. I have the air springs on the rear axle. My condition is that both air spring over fill to the point that the vehicle ride because very rough. It is also very noticeable that the rear is much higher than the front (stink bug stance). I can't find much in my Bentley manual about how this system works, but in the trouble shooting table, it suggests fixes to this problem are: The EHC control module is in transport mode (this is used by BMW at the factory and during transportation to the dealer--I'm not sure why it would suddenly be in this mode now after 20 years), replace the air compressor, and blow out clogged air lines.

The latter I can do, but if that doesn't work, I'm reluctant to replace the whole air compressor, "just to see". I have loosened/removed the air lines going to the air reservoirs to bleed the air from the air springs, and the systems then seems to work OK for a while, but after a couple of trips, the air spring are over full again. The warning message is a little sporadic. I have gotten the message from time to time (and I'm not the primary driver of this vehicle, so I don't know exactly how often) but it usually goes away and the message is not showing when the air spring are over full. I don't return any relevant codes with the scanners that I have.

Does anyone have any other suggestions how to troubleshoot this issue? I would suspect the drain valve (9), but I'm not even sure how it works as I don't see a vent to atmosphere any place. But I don't really understand the various schematics for the valves 7, 9 and 10.

Thanks.

[andrewwynn]

What scanner are you using? Foxwell will let you read the right height sensors.

Airbag is for protection in a crash air SPRING holds up the car. Just a minor quibble bugs me when people call them airbag nexuses that is an existing other type of device. Both highly useful but hardly interchangeable

[2mbb]

Thanks for the correction on bags vs springs. I corrected my first post (I have an E46 with an air bag warning but that's another story...).


I just got the Foxwell NT650 Elite--I got it to reset the air bag warning on the the E46. I did connect it to the E53 and didn't see any codes, but I may not have finished with the headlight diagnostic. I wasn't sure yesterday afternoon whether the E53 has Xenon headlights or not. I decoded the VIN and it says it does, so I'll check again later. But I don't necessarily get the air suspension failure warning light when the air springs are over full.


Thanks for your help.

[2mbb]

I gotta' bump this. After a period of no problem, my rear air suspension overfilled again. I pulled out the air compressor, bench tested the valves (all seem to work), removed the right side level sensor but didn't know who to bench test it.


I bled out the air, and once reconnected, the suspension goes back to normal ride height. It's been out on a few short trips and it's working for now.


My new NT650 elite doesn't seem to monitor the ride height sensors, but maybe I don't know what menu item to pick.


Any help would be appreciated!

[andrewwynn]

Ride height should be in chassis sub menu. Look for keyword level.

Live data maybe the sub sub menu.

[Rockit]

If this helps there is sensor in the rear that goes bad, Had mine changed. I only have rear air bags and ride height. I'm not sure but there might be one in the front too. You will see a pivot arm going into a box, they are mounted on the frame under the car.

I don't think the sensors are expensive.

[andrewwynn]

It's very common for the connecting rod ball joints to rust Frozen. Check all three (front right will have one also if you have HID headlights).

[Clavurion]

The front sensor is for xenon headlight auto level. The rear right sensor has two circuits, one for each system. The rear left is just for EHC.

[2mbb]

Sorry I'm getting back to this so late...Long story short is I replaced both level sensors on the rear axle and discovered that the right side air spring was leaking, so I replaced both air springs. This issue now seems to be resolved. My daughter has this car with her at college but I think she would tell me if the suspension was acting up again.

[andrewwynn]

The push rods will rust at the joint and cause all sort of chaos was that related?


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