I’v used VVDI2 key programmer to have 2014 Citroen ds3 pulled pin and programmed key in seconds
I got pin code in approx 10 second and programmed spare key fine.
key was supplied by customer, was new but aftermarket type, however the remote doesn't work.
Then i did it manually:
1) switch ignition on to position 2
2) press and hold down lock button for 5 seconds
3) after 5 seconds release lock button
4) switch off ignition , remove key and test remote
being a customer supplied copy key may well not be correct remote
repeat process for each key needed
Note: the correct remote is very important
there is ASK/FSK, 2 or 3 buttons and till 2006 and after 2006, also 315 and 434 Mhz, many types.. any type depends on the BSI installed.
Chinese cheap remotes they buy on ebay or aliexpress not always work, at the end locked and cannot be reused.
Better use xhorse vvdi2 remote keys, never locked - can be reprogrammed.