A small battery that fits in a key fob or remote.
CR1616
Probably a CR1616. Open it up and see what battery it takes.
Time for a new battery in the fob.
3 button fob 2003 onwards cr1616
Remove the valet key from the fob and behind it is a small Phillips screw. After that the fob will split and the battery is visible.
Open the key fob up and look see what battery it contains. Buy that exact battery.
what is the replacement battery for a 2003 Honda accord key fob
Open the key fob and remove the battery which has a # on it, and then buy a duplicate.
If you know for sure that the alarm is functioning correctly, but the key-fob doesn't operate - either the fob is faulty or the battery is flat. Replace the battery - if the fob operates the alarm, then the battery was flat. If the alarm still doesn't operate, then the fob is faulty. You can always test the battery with a multimeter - although you may have to dismantle the remote to get at the battery !
Lithium CR1632 (2008). I just replaced mine and got it from the dealer.
No, You do not need a key fob to start a car. When starting a car, you put the key in the ignition and turn. Power comes from car battery, not from the key fob battery!
You do not have to reset the key fob when changing the battery.