Key Remote Problem

[KeithOT]

My 2 button key remote had seen better days so I got a new case & flip key. I transferred the electronics etc to the new case & it was OK door locked/unlocked OK - However when I got in the car this morning all seemed OK but the engine would start but not keep going
I reprogrammed the ket to the locking & tried again engine started & ran OK but the l.e.d. in the door was flashing (ominous!) Got to work OK but this evening problem was back reprog got it going went to local VW Dealer (waste of time) wouldn't run again reprog got it going with accompanying l.e.d. flashing.
I assume this would be the same as fitting a new battery in the remote have I got a problem or is there a simple cure?

 

[Fl@pper]

you have likely left the immob chip in your old key or worse 'lost it'

won't run or program without it

 

[KeithOT]

Dead right but I can'tget the b****r out of the old case - nobody mentioned that transponder in other posts! didn't even know it was there thought it was all on the circuit board.
Thanks for the info