Self level susp inactive

CTSportX5 · #1 08-20-2012, 09:48 AM

For those who will scream use the search feature, obviously you haven't had to search this topic. There are what seems hundreds of posts and I wasted an hour trying to sift through them. Although I hate to add to them, I have narrowed down my particular case and am looking for a suggestion based on my symptoms.

Driving along last week this error randomly popped up on the cluster. There were 2 people in the back. I start up the car an hour later with only myself in the car, the fault is gone. I drive 30 min with no problem. The next day with 2 people in the back the error pops up again...so it seems to me the system senses the extra weight and wants the compressor to kick on, but the compressor never kicks on and the error appears. I have checked fuses and inspected all the wiring in the spare wheel area. All in order and dry too. During my search I read about the "air supply control unit" and a certain module that goes bad. I hate throwing parts at a problem not convinced it will solve the problem. Anyone have any insight for my particular problem?

BTW, it is a 2005 4.4 with rear air bags only. Thanks!

EDIT: Some extra info. The ride height seems normal (the bags are not losing air). It has felt a bit more harsh/ bouncy recently- probably due to the bags staying at a constant PSI..

TwinTurboGTR · #2 08-20-2012, 10:04 AM

It is odd. Did you try opening the tailgate and sitting on it? Usually if you do that, the pump kicks on, so if thats the case then the EHC should be fine. Another one to check is the EHC sensors in the rear that controls the ride height.

SlickGT1 · #3 08-20-2012, 10:15 AM

So the first thing I want to know is how is your battery? How is the alternator?

I agree with TTGTR otherwise though. Could be the ride height sensors. People sit in the car, it lowers it, and maybe puts them out of range.

CTSportX5 · #4 08-20-2012, 10:27 AM

Battery is new, alternator is charging as it should. The pump does not kick on with extra weight. When the extra weight is applied it seems like the car knows it (means the sensors are fine??), but the air pump does not kick on. I haven't heard the pump kick on for a while now.

The error resets after every start. If I drive around by myself or with a light passenger there error is not present. Its like it is stuck at the weight ratio setting the last time it worked properly.

TwinTurboGTR · #5 08-20-2012, 11:51 AM

I think those mechanical sensors are stuck. Not allowing the computer to communicate with the air compressor.

CTSportX5 · #6 09-03-2012, 08:21 PM

Alright so im a moron. Before calling the shop I decided to pull all the fuses one by one. I must have read the chart wrong and pulled the wrong fuse the first time. The very last fuse- 87 i believe was indeed popped. AND it is indicated as part of the air suspension on the chart. Replaced it and the pump is working again. Gotta love the free fixes.

Ricky Bobby · #7 09-03-2012, 09:42 PM

good to hear it wasnt an easy fix, my air suspension took me $1000 and 10 months to get working properly!

gdlbmw · #8 09-05-2012, 06:23 PM

I am having the same problem as CTSportX5. I just changed my 87 fuse (air pump) to a new fuse and the message is not coming on the dash anymore however the warning exclamation mark is still on.

Any thoughts on how to reset this?

Thanks!

CTSportX5 · #9 09-06-2012, 10:50 AM

Warning exclamation mark? The only indicator for me was the message on the cluster. Perhaps this is a separate fault, maybe low tire pressure light?

TwinsPoppa · #10 09-06-2012, 11:54 AM

I think there are three warning lights that have an exclamation mark.

1) Flat Tire Monitor
2) Automatic Transmission
3) DSC/xDrive (4x4)

Canadian models have a different light that also has an exclamation mark but I assume you don't have a Canadian model.

Since you had the SLS message, is it #3?