I need help to find out if my key fob battery is poor or if the diversity antenna is bad. (I have good radio)
The thing is that i have to stand next to the car to unlock and lock the car but i want to be able to do it like a brand new one with couple of meters away. I only have 1 key so and the key is like this



And it's the "non battery change key fob"

Any idea how to find out which one is the faulty one or needs a "repair"

 

if you're having ot push the button several times before it unlocks, even up close, it's probably the fob.
If it works all the time as long as you're close enough to the car, probably the antenna.

 

i tried it and probably the fob then.. sny idea if i can change the battery in it or do i have to buy new key fob? :/

 

@RinZzan, you would have to buy a new FOB. This is a poor design feature for that key style. So basically every few years, when your FOB runs out of battery. You have to buy a new key.

Symptoms are, sometimes it works and sometimes it doesn't. That's the battery going low. Eventually it will stop working all together, the good news is the replacement FOB you buy doesn't require to be programmed to the car. Just stick key in and go.

 

check youtube, there is a way to replace the battery but it requires surgery and a delicate hand. I agree with the others, sounds like the rechargeable battery in the fob is on the way out.

 

wow I have the problem but I have a battery n my fob. just replaced them in both find. so my issue must be the antenna

 

think i have the same problem it worked on one key then died and did not work no more , so i bought a new OEM key from BMW, that didnt work so now i have two keys which dont work, not sure what the problem is but i have a 2005 E60 530i BMW which has only 2.000 miles on the clock, all indications state it is the diversity antenna but only 2.000 miles on the clock, what the hell is going on ? the new key cost me £146 from the dealer, they said book it in for a check , yeh £130 an hour, i cant wait

 

i would probably state that its the antenna after that haha.. but i would rather change it myself since they are expensive

 

The FOB can be cut open with a dremel or small hand saw blade and the battery can be replaced.

Put it back together with hot glue and if the seam is ugly get a silicone sleeve for it.

 

Rinzzaan, any update - did you fix it?