So the BMW gods were looking after me yesterday.....

[Roundal]

The battery in my key decided to go flat and the car refused to lock, luckily right in front of Auto Atlantic!

Just a question: if the battery is totally dead and you open and lock the car with the key, will you still be able to start the car? Why do you only have 60sec in which to change the battery otherwise the key has to be recoded?

 

[Sankekur]

You should still be able to start the car even if the battery the key is dead.

It might be that they use dynamic RAM to store the codes on the key, but doing this will result in instant (for all practical purposes) los of the codes. But doubt whether they would use a system like this, codes would most probably be stored in some sort of EEPROM.

 

[Reuben]

The owners maul stated that the battery charges when the key is inserted into the ignition. I suppose all batteries have their lifespan. As for the memory, It does not rely on the battery power. The battery is required for the RF section of the remote, ie, to send the lock and unlock signal to the car. Regards. RP.