The part #'s available for our year will include the BT function you will need. BMW Assist will not function after the upgrade. I'm not even sure anyone is answering phones @ BMWAssist anymore. ;)

Yeah, I probably went through 5 phones in the 1st year. Cleared it while I was getting a windscreen at the dealer last year and have 2 other phones since.

Thank you PropellorHead! So if I am searching FleaBay for a used one, any idea if 2005 and later will work?

08 2008 BMW X5 TCU TELEMATICS CONTROL UNIT 84109171348 | eBay

The BT ULF part # was 84-11-6-946-993.

Well I will try the one listed out of a 2008 and see how it goes. The one I am trying is 84109171348. I see some claims that is is compatible with BMW 2004-2012. For $50, no real loss if it doesn't work.

If searching ebay for used BT modules that work...go back to post #8. I placed a direct link to the part database that will give you a list of old & new TCUs that will work and all were used during after the 10/04 date.

Again, if you click the link in post #8...you can compile a list of multiple BT module's 11 digit part numbers that can be used to shop with...and you'll also know those part numbers will fit/work for your model's application.

Regarding BMW ASSIST...the most crucial need for having it installed would be the built-in microphone in the headliner panel that facilitates Voice Commands & the ability to answer & make hands free calls.

Post #8 on the 1st page has a direct link to the part database for the e53 TCUs. If the number is listed (old or new)...then all is well.

If the number you posted is not listed...then paste it into the part number search box at the top of the linked pageand you can see which bmw models it was installed in. There's no need to waste time & money for a part that may be for new gen BMWs with iDrive.

Just because it says it fits a BMW between 2004-2012...doesn't mean it includes the e53. There are multiple models with the newer communication busses (IDrive) like the e60/e65/e90 that were new gen BMWs that started production during the same time the old gen e53 was coming to the end of production.

You need MODEL numbers...not just build date numbers on sites like eBay that may not have complete details/info. Again, 2004-2006 BMW fitment may be totally correct...but totally wrong if referring to an e53 X5 vs an e60 5 series BMW. :)

Yeah, it's all pretty confusing. So many posts from as far back as 2006. I read the 993 model PropellorHead listed does not support voice commands so I am trying to find one that will firstly replace my faulty TCU and will allow bluetooth to work and utilize voice commands. The VO in my X5 does show telephone preparation so as long as the unit plugs in and powers up, we will see. I can use PA Soft to write VIN and I did save the program data from the existing TCU.

There are 24 part nbrs at this link: Single parts SA 639, trunk | BMW X5 E53 X5 4.4i N62 USA

All of them are listed as (#1)...some are no longer available (new) but are out there in the used market...but all will work for e53 owners. Shop for a BMW TCU using ANY of those 24 part nbrs...and it will give you results for a TCU that is plug-n-play.

TCUs with a build date printed on them prior to 10/04...will probably not have what you need. And if you shop for a TCU from a new gen BMW (like an e60/e65/e70/e71/etc)...they may not be compatible since they were designed to communicate on the (I believe) MOST bus which our e53s do NOT have.

I can't verify if the TCUs designed for the new gen BMWs will work (someone please chime in if you know for sure)...but with the ability to quickly find out which BMW models are listed for a part nbr using the database...I'd personally stick with the multitude of part nbrs listed as being compatible and exchangeable for the e53.

Good luck. :)

Yep, you are correct. The unit I bought is the MOST Bus. :( Oh well, back to searching...