Changing battery on remote unit

[Slobicus]

My Saab 9-5 (2011) displayed message saying remote key battery needed to be changed. I have removed the cover and changed the battery for another CR2032 but it foes not seem to work. I am wondering whether it now needed yo be synchronised. There is a keyless ignition system, so nowhere to insert physical key apart from the doors. Can anyone help ax to what the problem might be?

[jmblack]

I think you have to press it 4 times to synch?

[Audax]

A total guess based on reading WIS (which is unhelpful about how you replace the key battery) might be to drop the key into the cup holder.