Telemetric Battery replacement and Location

[RVSATDUDE]

This is my first post and thought I'd contribute to a forum that has entertained and educated me. I hope this helps someone
I have been battling a SOS Failure for a long time. Then I read in one of the forums that a possible cause of the SOS failure could be the back up battery.

Scanned for codes and sure enough the Telemetric battery is showing bad.
Great no problem. Called local dealer and asked for the battery which is basically 4 AAAA Lithium batteries w a plug on the end. No problem I thought. After researching location of the Telemetrics module and not finding anything online I thought I'd just start digging. I could find pics of the module itself but nothing on where this bugger was located.

I started in the trunk thinking it might be stuck in there. No dice. Ok maybe behind the rear seat. Ok Now how do I remove rear seat. Nothing on that either. Well its really no big deal to do any of this so I thought I'd share on here so if anyone else runs into the SOS failure they can at least try this. Its possibly one of the cheapest fixes for a M6 and probably the 650.. I have a 2014 which is the new body style and so would probably be the same for many years.

Module is located behind the rear seat on drivers side.

1st Run both seats forward to allow access to the seats
(mines a convertible so I didn't have to go to far)
2nd Remove the headrest - This can be a challenge but wiggling it back and
forth I finally got them out.
3rd Pull on the bottom cushion straight up on both sides. My son assisted
me in doing this. You will not be able to pull the bottom cushion out but
you really dont need to.
4th Below the back portion of the seat is a Torx 40 bolt. These both need to
be removed from both sides. Now remove the back section.
5th On the Drivers side you'll see a black box with a lid on it. Slide the lid
off and you will see the battery. Simply unplug and plug in the new one.
6th Setback and pat yourself on the back.. Now put it back together

Battery part number for my car was 84 10 9 297 787 and sells for $32 plus tax.

[ezmaass]

Thanks for sharing - always a good feeling when you can get the job done yourself!

I wonder what made them fail, though? Seems quite young if they were rechargeable and only used as a back-up for the SOS system?

That said, even the main battery seems like it doesn't last long on modern BMWs. BMW wants to replace them every two years - crazy considering a main battery should last around 5 in most vehicles (easily). On my last two BMWs (current 650 and former 550), BMW replaced the battery at two year service - no sign of wear or issues that I could tell, but they're instructed to do so.