Hello everyone!

New to the forum as well as the new owner of an 09 535xi Sedan, 149xxx miles, AWD, Twin Turbo, with full intake and exhaust, tuned on e85, with LED lights and Angel eye headlights and an expensive Radar Detector.

Now my problem!
I know this has been asked a million times but I always get confused reading another post so I decided to make my own to get some opinions on people who know more about the platform than I do.

I have 2 keys, the previous owner had 1 key and the fob stopped working so he went and got another key but that fob never worked. So now I have 2 keys but the fob doesn't work on either. Since owning the car I have just used the ole' fashion turn key like any other car but it sucks when its really cold or I'm trying to grab stuff from the car and I'm needing the fob. I can't pop these Keys open to replace the battery either, my guess is a transmitting error somewhere? I do know that I walked out of a Best Buy just a few days ago and my keys were in my pocket and my Alarm went off? My girlfriend was in the car and it was locked and she said she didn't touch anything so I don't know.
I don't really want to venture to the dealership to get a diagnostic seeing as they're going to charge me $200 just to look at the issue... I've seen some posts about an Antenna Amplifier Diversity or possibly a broken wire in the harness near the tailgate hinge or some sort of module apparently according to PCS is a common fault initiated by damp.

SO! I have no idea and I'm looking to get some opinions to fix it maybe DIY it.

Thanks ahead of time for the assistance! I look forward to being a member around here!

 

Sounds to me like you just need a new key... Did the previous owner state they he got a 'new' key? When I bought my car it came with three keys total from the original owner (two keys and a third 'valet' key).

And as far as I know, when a key goes bad then that key is just dead and you need a new one. They have a sealed rechargeable battery that charges whenever it's inserted in the car and the car is on. I've had one of my keys die and only the actual key works and none of the buttons do. I just swapped it out with another key of mine and the second key works, buttons and all.

So maybe you just have two dead key batteries...I think a new key from BMW would cost you around $200.

PS: I think your girlfriend did touch something as the alarm doesn't normally go off, especially since the buttons on your key doesn't work. She may have tried opening the door for some reason and when the car is locked and a door is opened without the use of a key the alarm goes off. Something else could have happened, but I know the alarm goes off when a door is opened without using a key.

Edit: Why not get this resolved prior to the purchase? lol. Might've been the simplest thing to negotiate the price or have him give you a functional key.

 

She honestly probably did but didn't want to tell me haha!

And yes he said that he got a new key from the dealership and it has never worked ( I trust him because he's my brother and we work together, literally ) And I'm pretty happy price wise $8000 and its in great shape, little bit of aftermarket it's a really nice car, I'm about to do a full fluid change today as well as a new battery, I'd just like to get the key situation handled. It's at home right now so I can't play around with it until I get home from work but they have have given him a Lemon, I don't really know.

But thank you for the input! I may have to end up just sucking it up and going to the dealer for a Diagnostic.

 

The dealership sold him a brand new key and he left the dealership without the key working? There’s something wrong about that. It could be something with the car but I don’t see why you would walk away from the dealership without a fully functioning key. They should have programmed it to the car to have it work and everything.

Edit: As far as I know, dealers are the only one who can get you a new and fully functioning key. The ones online and stuff don’t ever work so don’t waste your time and money. If he recently bought they key then go to the dealership and see if they can see what’s wrong with it. Hopefully they don’t charge you for fixing what they messed up. and hopefully it’s just the key.

 

Oh okay wait I talked to him a bit more about it, and he got the second key off Ebay and had someone cut it for him. When he got the car it only had 1 key but the buttons never worked. So I guess it is very possible that I need a new key!

 

Actually, it sounds like you need two new keys!

 

Haha I knew something was up. You can only get keys from the dealer. The first key he had the battery probably died. They charge like $200 for it I think.