Here is the guide to program remote key for Smart 451 2012 by using SKP1000 key programmer via OBD.
Model:Smart BR451 2012 yearKey Type: Straight Remote Control Key
Device:SKP1000 tablet auto key programmer (Chinese version is CI600 Plus)
Select model: br451
Select immobilizer system
Select OBDII connector and turn ignition switch to ON position
Click Yes to continue
Current key number: 2
Select Program Key
Maximun 6 keys can be programmed
Click Yes to continue
Program key success will generate remote automatically
Turn ignition switch to ON position
Configuring…
Wait about 1 minute
Turn ignition switch to OFF position
Turn Ignition ON
Program success.
Continue to program next key? Press Yes to continue, NO to go back
SKP-1000 Program Smart 451 remote key success