Lost working key you need to purchase a blank of a new key and cut it to work with the switch (castle) ignition installed on the vehicle. Then follow the immobilizer learning procedure (see «Learning immobilizer keys»), by applying the existing training and new working keys.
If the learning key is lost it is impossible to perform the key learning procedure. This means that you can continue to operate the car only with the existing working key. If the remaining working key is lost or if the immobilizer malfunctions, both the immobilizer and the ECU will have to be replaced with new ones. After such a replacement, you can cut a new training key blank to work with the ignition switch installed on the car, and carry out the learning procedure (see «Learning immobilizer keys»).