Monaro Key

[Monaro5.7]

My main key for the cat has just stopped working. And last night when i lifted wrong key the alarm went off so car is defo not reading key.

So my question is will it just be the battery in fob?

Key has lasted about7 years so cant complain

[Monaro5.7]

I have changed over the plastic body before as my main key has Holden emblem on the back of it so i might just do that again and change battery or try the key in the ignition see if it charges.