Over the past 12-14 mo. I've dealt with SLS(self leveling suspension) issue on my 4.8is and tons of frustration. So far I had to replace ride height sensor $98 (unnecessarily), both suspension airbags over $1200 (I guess it was needed, "R" one was leaking air -used Arnott for both sides).
Right after the bags were replaced I used GT-1 utilizing control unit functions test mode: raise the front axle or/and individual bags side by side I filled them with air, and almost perfectly leveled it with measuring tape ground to the fender. However, SLS message was still up, level adjustment function - NOT working, and no LED's on the switch.
So, I went to "stealer" again to reset the air-supply control Module (was told it is resettable). All day at the dealer and $263 later (for trying) I came to pick up my x5, and found it completely distorted-uneven, and according to them "unsafe to drive" (it says on the receipt from BMW of Bellevue). Front driver side way up high (way out of the norm), passenger side low close to the fender. NONE OF THE SLS ISSUES WERE FIXED. MESSAGE is still UP, NO FUNCTION; only LED light on the switch is blinking in the middle now.
It was my 6th or 7th visit already, and I was so pissed off. All I asked advisor for is to bring it back to the level/condition I brought it in yesterday. Service advisor said it is not possible and now requires replacement of the Module and more re-coding done for a total of $1700. In fact He mentioned that technician already tried to calibrate/equalize it, and couldn't do it. Car went back to its new grossly uneven level again after they drove it for less than a mile. At that point he sounded completely incompetent, so I did not want to proceed with anything they suggested.
NITROGAS2000!!! I beg for your advice. You have had very similar issue for a while, and now selling your EHC-2 Module on e-bay. My question to you is why are you selling your module? Should I purchase new Module from a dealer, or try to recode an old one using GT-1, or something else?
My guess is you either have fixed SLS by now or traded your 4.8is in. Please, share your wisdom. Thanks.

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4.8is wide body - WA