Anytime a battery cable is removed from the battery the radio will need to have the clock reset and the radio stations re-programmed. (Helpfull)
Check your fuse panel for a blown radio fuse.
Any time a battery cable is disconnected the preset radio stations have to be reset and the clock has to be reset ( if that is what you are referring to )
The radio doesn't have a battery. It uses the vehicle electrical system / battery. If the power to the radio is interrupted, you will have to reenter the presets. Make sure the fuses for the radio are not blown.
What model corolla?
It seems like your radio is damaged. You can try to reset the system by taking out the battery, if the radio is in your car.
To fix the CD error code on a 2002 Ford Explorer SportTrac radio, start by ejecting any CDs that may be stuck in the player. If the error persists, disconnect the vehicle's battery for about 10 minutes to reset the radio system. Reconnect the battery and power on the radio to see if the issue is resolved. If the problem continues, the radio may need professional servicing or replacement.
Depends on the vehicle you're asking about which you did not list.
The Explorer will need to relearn its idle etc ( drive cycle ) and the clock and radio stations will have to be reset
There is no way to disable the theftlock really. You can google it, and find out the password for your radio, and then change your battery, and then enter the code.
I believe that is in the center stack of the dash and that the radio has to be removed if you need to change the GEM
I believe that is in the center stack of the dash and that you remove the radio to change it
My 97 explorer has a battery saver relay in the center of the dash, between the steering column and the radio (closer to the radio) its by the big computery looking box thing with a bunch of wires coming out of it (that box thing by the way is the Generic Electronic Module, or GEM, which you'll want to know if the battery saver relay is not the problem). The system should be about the same in 95-99 (I think).