Loss of radio settings and stored data- All cars and trucks

yes, and in case if I need to change the battery on any other car then before replacing the car battery I simply attach a 12 volt trasformer (rated at DC 12volts and 3Amps) or a jumpstart-battery to car-battery-terminals using clips to avoid the loss of car radio code, clock settings or other BSi settings.

Usually when you replace the battery, you lose the memory settings on your radio, power seat memory and any other accessory memory settings. The engine might also have to go through an idle relearn process. The engine might run erratically until this process is completed. One way to avoid this problem is to install a memory saver, available at most parts stores and are relatively inexpensive. They come in two types. One uses an electrical outlet and the other one uses a square 9 volt battery. It plugs into the cigarette lighter or 12 volt adapter. Install the memory saver and leave it plugged in until you are done installing the battery. If you use one of these, then you do not need to reset anything. If you don't then you might need to reset your accessory memory functions and have unstable engine operation until the idle relearn is completed. Although the computer will correct the problem on its own by driving it, you can speed up this process by performing a manual idle relearn procedure.
1. Start the engine and allow it to run in park position with all the accessories off for one minute.
2. Put the transmission in drive with all accessories off and let it idle for one minute.
3. Put the transmission back into park and turn all of your accessories on for one minute.
4. Put transmission into drive with all accessories on for one minute.
I hope this information is helpful to you and thank you for using Fixya.com.

TURN OFF RADIO FIRST BEFORE DISCONNECTING THE NEGATIVE BATTERY CABLE BUT.THATS NO GUARANTEE YOU WILL LOSE RADIO CODE I WOULD TRY TO USE A BACK UP MEMORY SAVER YOU PLUG IN THE CIGARETTE LIGHTER BUT NO GOOD IF CAR GOING TO BE DOWN LONG.TIME BECAUSE THE MEMORY SAVER BATTERY WILL GET WEAK YOURE IN TROUBLE.BMW WARNS IF YOU DISCONNECT BATTERY CABLES YOU WOULD LOSE HEATING COOLING CLIMATE CONTROL.YOU ALSO WILL LOSE FUNCTION TO WINDSHIELD WIPERS AND WASHER , CENTRAL LOCKING AND THEFT SYSTEM CONTROL.

On most cars after 2000 it is recommended to keep a minimum of 9 volts in the system when disconnecting the battery.
You can buy a 9 volt battery unit to plug into your lighter socket.
Otherwise....if you have a battery charger....attach it to the alternator output and put it on its lowest setting....that should keep voltage in the numerous memory circuits while you change the battery.

When changing the battery.....(removing voltage from the system) it's a 50% chance of putting the radio into theft mode.
The codes to take it out of theft mode are available online.....just google.