DTC P1622: Key Id Number Does Not Match: Condition
WARNING: This page is about a different car, the 2002 Mazda 626. However, it is still accessible from the selected car via links, so may be relevant.
DTC is set when ID number stored in Powertrain Control Module (PCM) and immobilizer unit does not match. Possible cause is Immobilizer system reprogram procedure was not performed correctly after replacing immobilizer unit.