4x4 Light - Driving me nuts - 06 4.8iS
 

I'm going NUTS!

Occasionally I get the 4x4 light when driving. No other light except 4x4 comes on besides the constant "suspension level inactive" light which is caused because I never coded it out after my BC's. Both lights will go off when I turn the ignition and stay off. Sometimes the 4x4 light stays off for weeks sometimes a few days.

I replaced my transfer case motor (and took it apart to find a chewed up gear) about six months ago. Recently I warrantied it and put a genuine/brand new motor in again.

Last night a friend scanned the truck for me and came up with the following:
53FC - Supply, Control Module: Terminal 30
4F7A - Signal from Transfer Case Faulty
5F3A - Transfer Case Internal

I unlocked the OBC and checked the voltage. When off it read 12.1 and when operating between 13.8 - 14.1. I am at wit's end with chasing this. I considered putting a new alternator and battery in just because but at 80,000 in a MINT vehicle with an original battery and alternator I just think its silly to throw parts at it.

1) Is it possible my voltage is spiking? My girl drives the truck and she said the last two times it came on the radio shut off simultaneously and than turned right back on.
2) Is it possible the transfer case module took a dump? Keep in mind my trunk is BONE dry and sealed. ZERO moisture or water get in there.
3) WHAT THE F*^&?

I'm well past the honey moon phase of this thing and I never use it. It solely her vehicle these days. Any ideas or experiences with the same thing?
Currently on my second transfer case motor AND flush along with a laundry list of other things I've addressed with the truck.

I read this thread for those of you who are going to accuse me of not searching:
http://www.xoutpost.com/bmw-sav-foru...only-help.html

but it didn't describe my exact issue.

Olek, leave the OBC test on while running and have your girl give you the reading when it does the weird radio shut off thing. If it spikes above 14 or below 12 it might be the Voltage Regulator on the alternator which I've seen some 4.8iS need to replace.

The transfer case codes are weird though, is there a separate control module for the Xdrive transfer case? - I do not have much experience as my '03 has the mechanical Xfer case

I can't leave the stupid test on because the "suspension inactive" light flickers every time you hit a bump and I haven't had time to get it coded out.
The xdrive transfer case's have their own control module which sometimes goes bad from what I read but its almost always caused by water/moisture. I don't even know where its located.

Welp if you had it coded out you'd know if it was under/over Voltage LOL

Does anyone live near you with SSS or is there a shop with Autologic that can code it out of the Vehicle Order (VO)?

Stripped splines on the front driveshaft?

Just throwing out there, I have no experience with the x-drive...

^^Thats a pre facelift issue with the mechanical case and driveshaft

I have one guy that has autologic and NO clue how to use it and another friend who I can't ever catch to get it done. Last option is driving to NH to a friends shop which would require taking time off from work. :dunno:

Pre-facelift issue and this one is intact. The car also has two brand new GKN axles, a new steering rack, brand new tires front and back, etc.
Its a pretty flawless vehicle which is why this is so infuriating.

wow we're in the same boat, I haven't coded out the suspension level inactive light and my 4x4 light keeps popping on. I think mines the transfer case though. Need to find someone who can read the codes for me

So if my front driveshaft strips, I'll still be able to drive it?

^Nope if it strips out completely you are toast until you get a new output shaft and driveshaft