re programing my remote key 1998 300tdi

Hi guys
I have 1998 300 tdi but battery gave problems, changed the battery but now my remote of the keys is not working so the Landy keep on showing yellow key light as soon as i try to start.
the remote also won't unlock the truck
Is there a way i can re program the remote by myself?
I did put in the access key code so the truck runs but can't lock the doors.

Hi to you.
I’ve never heard of re-programming a D1 remote fob, but after disconnecting and re-connecting the vehicles battery the fob has to be re-synchronised to the security ECU, simply done by pressing the lock button on the fob around 4 times the central locking will then lock.
So assuming the fobs battery is okay and no interference in the area of the security ECU then the fob is possibly faulty, and will need to be repaired/replaced.

In the UK theres a company called ‘remote key’ that would carry out that work of checking as necessary and supplying a replacement fob if required.

That 4 times press has worked for me as well to resync -