OK , I've already solved the problem, but I'll retell the tale for the benefit of the forum.

My wife dropped the key fob to the 04 CS. It hit the floor quite hard , splitting the case popping the battery out.

Reassembled it putting the battery back in.

The remote now refused to unlock or lock the car.

The green light on the fob flashed when the button was pressed, but the car did not respond.

I could unlock the drivers door manually with the key, but the alarm sounded until I put the key in the ignition and started it up.

I searched the net for a solution to reprogramming to locking function without much luck, but eventually came across a vague description (on a website which I since
cannot locate again)

Anyway the description said , Unlock the vehicle, then hold down the lock/unlock button for 20-30 seconds. So I did this (while sitting in the drivers seat with the door closed and counting to 30).

Believe it or not, it worked !! Remote is working again !

Hope this helps somebody !

 

I have the same issue with the 997.1tt with key 2 which does not remote unlock/lock, but works on the door and the ignition, though key 1 is still fully working.

 

Thank you! I tried so many options and none worked. Two different dealers were absolutely worthless and wanted to charge $199 for a diagnostic or $400 for a new fob plus programming. Your idea worked and the fob is perfect.

 

Awesome ! Glad the post helped somebody