Have problem with my keyless key on 2009 c6 cdya. Master key worked well until i accidently put it in washing machine. Now if i changed battery key is not working, red light flashes only. If i open car manually then alarm goes on and i have to start car fast with that key then alarm goes off. Now if i use spare key i can open doors with it on key buttons but keyless function is not working. Is it possible to reprogram master key at home or should i go to dealer or may that key be damaged after being in water ? How can i activate keyless funcion on my spare key ?

Thanks

Time to get a new fob

But if i put a new battery in it red light keeps flashing all the time, does that mean that key is broken ?

The flashing means that the fob does not sense the car. Since you just replaced the battery, it failure to sense the car probably means that the fob is broken and needs to be replaced.