Hi,

I just purchased a used E61 a few days ago. This morning, after a hard rain and cold freeze overnight, the keyless entry is no longer being recognized by the car. I tried changing the battery; no luck. The key still works when in the ignition. Is there a reset I have to do, or some other easy trick? I have no idea if the weather played a role, the car was completely iced over, although it has warmed up and thawed out now. It was fine the first 2 days!

 

What kind of key is it? If it's a 'comfort-access' type of key, then you can replace the battery in the key fob.

If you have a spare key, try with that. If the symptoms persist with the second key as well, then very likely, the diversity amplifier needs replacement. If the second key works fine, then you will need to either replace the battery in the key fob or get a new key.

 

There a a lot of threads going around lately about battery high discharge and what things are affected when ur battery is on its last legs. For me, comfort access not working was one of the issues I dealt with until I replaced the battery. The car starts shutting down systems to preserve voltage when it gets low.

 

Actually the diversity antenna does not control the comfort access, the comfort access has about four antennas inside the car and trunk. Make sure to try all the doors or try to start the car with key in pocket.

If you replace the battery and it is still not recognizing it then the key probably lost the profile somehow. You can easily reset it or check if you have DIS. I have the procedures so if you have DIS just let me know.