XSeries-forum

Hi all

been having this error for a while now, it seemed that the old battery was dying, it was certainly sluggish to start after a while sitting. I replaced the battery a couple weeks ago, but it hasn't made the error go away. Every day I get the same thing, if I drive the car then stop then start it up again after a short time, there's no error, but certainly overnight, the error is always there in the morning.

any ideas what could be causing this battery drain?

thanks

Have you coded the replacement battery to the car? If not then it needs doing as you cannot simply swap a battery out for a replacement without telling the onboard electronics it has a new battery.

https://bimmertips.com/bmw-battery-regi ... explained/

Did you charge the battery before fitting it? Shop batteries can be on the shelf for months and may slowly discharge. Unless you either go on a long run (100 miles) or charge the battery independently it could still be low. It takes 20-miles just to put the starting charge back. I charged my new X6 battery for 8 hours before using it.

Is your alternator producing the right output? For a car coded for (and fitted) with an AGM type battery you should see 14.4V with the engine running. For a ‘wet battery’ that should be 13.8V. The battery should be showing not less than 12.6V (it’s a new one after all) four hours after last use and with the car asleep. You need to pop the bonnet and then lock the car, leave it for 4 hours, return and lift the bonnet and check at the jump start terminals in the engine bay.

If it has been coded (correctly) then is the car actually going to sleep? Check that there are no tell-tale LEDs lit after 15mins or so. Apart from the alarm light nothing else should be on. If it is then something is keeping the car ‘awake’. That needs either a fault code read check or a process of elimination fuse by fuse to see which circuit is stopping the shutdown.

There have been reports of the IDrive systems / parasitic drains on the batteries on certain cars, may be worth pulling the fuse and seeing if it stops the drain, also checking if the car is going to sleep