Not enough info to be of help. What is the part nbr of the TCU you installed?
The 2003 X5 didn't come with BT capability...it had to be added as an accessory/option...and at that time, I think it required more than pressing the "talk/speak" button. Depending on if you had a telephone installed...it would require pressing the button on the phone's cradle.
If you have the newer TCU that was used in the 10/04-up e53s that came with the premium package or BMW assist...to pair a new device only required turning the ignition to KL R (ignition position 1) or KL 15 (ignition position 2)...which opens a 2 minute window to pair your smartphone.
Here's a direct link to a reply I made yesterday which has a bit more detail about BT pairing if you have the newer TCU:
https://www.bimmerforums.com/forum/s...7#post29751427