I tried to replace battery in my E39 key. I checked the old (original) battery and it was showing good voltage. Even then I replaced it with new one. The key remote is still not functional.
When I put the new battery in, I was able to program the key successfully. I was able to lock the car with the new battery, but was not able to unlock it. The locking mechanism worked (with new battery) for two-three times and then it stopped again.
Any idea what is happening?