Technical Description (Comment)
WARNING: This page is about a different car, the 2008 Mitsubishi Lancer. However, it is still accessible from the selected car via links, so may be relevant.
Assuming that another keyless operation key has already been registered with KOS-ECU, if the registration of the keyless operation key ID fails when a new keyless operation key is added or the existing key is replaced, KOS-ECU determines that there is a problem.