renault clio IMMOBILISER water damage?

my ariel leaked and wet my IMMOBILISER sensor the car starts when i press central locking button near the gear stick but thats annoying as the car wont start by just
putting the key in an setting off as normal......will i need a new sensor or just key re programming? ive tried putting the code in but the light doesnt slow down flashing for me to do it any ideas cheers x