This video describes how to add a key to a Daihatsu Copen immobiliser, and should also work for a Daihatsu YRV.

This video and instructions are not needed if your key has been cloned from an already programmed key, and should only be used if you are programming a key's transponder that the immobiliser has never "seen" before.

During this process, all keys except the black master key will be forgotten, so ensure you have all keys available when doing this method.

The following steps have been confirmed as working.
1. Connect the terminal T to Terminal E on the DLC / OBDII port
2. Insert the master key into the ignition
3. Turn on the ignition (do not turn over the car)
4. Turn off the ignition
5. Remove the key from the ignition
6. (Withinn 10s) turn on the ignition using the sub key
7. Turn off the ignition
8. Remove the key from the ignition
9. Repeats steps 6-8 using another key
10. After the final key removal, wait 30 seconds.
11. Remove the OBDII short

Terminal T is OBDII pin 13 and terminal E is OBDII pin 4