Tail lights unreliably light up when unlocking vehicle

[ChrisCote]

Originally Posted by Adam135

I left my car connected to a Battery Tender Plus over night. When I unlocked it this morning the tail lights and AEs lit right up Will look at getting the battery replaced. I hope this helps someone else out in the future.

any new info? my car just started having the exact same issues as yours

[Adam135]

Originally Posted by ChrisCote

any new info? my car just started having the exact same issues as yours

Faulty battery. Has been fine ever since it was replaced.

[rking117]

I hear a lot of talk about coding the vehicle to the battery. Can someone explain why this is needed? THis has probably got to be the most idiotic thing i have ever heard. Next I guess we will be changing our headlight light fluid too. But seriously, is there an article out there that explains why? It sounds to me like they got cheap on us by not placing a voltage regulator in place to maintain constant volatages to the vehicle. So they want us to pay extra to plug in a simple cable and tell the vehicle this is the new voltage take note.

That is kind of like having to have BMW plug in my Z4 to release the rear brakes so that we can simply replace the rear brake pads. (yes its true). I wonder if BMW forgot that we like to work on our vehicles ourselves sometimes.

[Bill B.]

Originally Posted by rking117

I hear a lot of talk about coding the vehicle to the battery. Can someone explain why this is needed? ... I wonder if BMW forgot that we like to work on our vehicles ourselves sometimes.

Oh, they didn't forget. In fact, they work really, really hard at making sure you can't do your own repair work.

The reason for the battery coding is that the charging cycles used are based on the age of the battery. The car doesn't know the age of the battery until it is told by way of the coding reset. Also, if the battery type/size is changed, it needs to know that too, as it uses different charging parameters for those things.

[deletedgone]

+1 about the repeated locking/unlocking. After a few times in a row, none of the exterior lights come on after unlock. I noticed this when gawking at my newly installed LCI's