E61 key not working

[anonymous-user]

Bit of a weird one, our E61 535d has two keys. My key works fine. My wife's key pairs with the immobiliser and starts the car but cannot lock or unlock the vehicle.

Short of it being a faulty button, I'm thinking it might be something to do with an aerial/transmitter inside the key fob? Is there anything I can check or replace or is this a trip to BMW for a new key and coding?

[bigdom]

It's unlikely to be the keys. I'd suggest its a issue with the Diversity radio/antenna that sits up under the rear spoiler on the rear window

[Elliot2000]

If that was the case then both keys wouldn’t work. It’s just down to the key- do any of the buttons work? Could be the rechargeable battery has given up.

You can cut the key open and solder in a new one- it’s a bit of a bodge. Or try sticking it inside a charging coil to see if you can get it back to life. Or if you have comfort opening - the battery is replaceable anyway

Or get an auto locksmith to make a new remote key

[anonymous-user]

Just to close this out, one of the rechargeable coin batteries had died. It wouldn’t unlock the car but when inserted into the ignition (non comfort access) the car must have given it enough power to ‘handshake’ with the car and start the ignition.

Coincidentally, the ‘good’ key also started displaying a low battery warning despite being charged in the ignition for 40 miles each day.

Ordered a couple of replacement rechargeable ones and unsoldered old and soldered in new and all seems well with both keys now.

That’s nearly 12 years and 144k miles on the originals.