Hey jwilb4! I see you're in CR as well. Good to know there are more xoutpost members from here too.

I'll try helping you with my short knowledge and expertise.

That error is referred as a speed sensor, to be more precise, the output speed sensor of your transmission.

It doesn't necessarily means you have a bad sensor or broken trans, it could be a sort of things as you might know by owning a X5.

It could be trans fluid needing a change if you haven't done that recently. Also it can be caused by a bad or dying battery, so you should check voltage just in case (you can do that with the OBC "hidden" menu), a bad harness. Believe or not, it could be caused by something like a vacuum leak too, but only if you get other errors in the DME.

Check all the errors you get, mainly from DME, EGS, and DSC just to make sure.

I don't think our cars have a transfer case control module because that sounds more related to the xDrive feature that came with later models, but it wasn't present in models from 1999 to early 2003 (before facelift). So, I would discard that.

Anyway, try to get as many codes as you can. If you are unsure what's going on, or don't have anyone to get them, ping me back, I can help you out if you're not too far from where I live. I have INPA with me almost all the time, I'm kind of paranoic with scanning errors and issues that have arised (and may arise).

Regards!

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BMW X5 2002 4.4i V8 - What a headache!!!
BMW X5 2019 XLine 3.0D - Loving it