2006 Hyundai Santa Fe SUVs had two different body styles. Each used a different factory keyless entry system, and the remote transmitters for the two systems are not compatible. While both keyfobs have three buttons, they look totally different.
2006 Santa Fe vehicles with the old (pre-2006) body style use a more rectangular-shaped remote with unlock, panic and lock buttons all on the front of the remote. This remote has FCC ID OSLOKA-240T and a Hyundai part number of 95411-2xxxx. See the old-body-style remote – Remotes Unlimited part 725-1725 – at this link.
2006 Santa Fe vehicles with the new body style use a chevron-shaped remote with lock and unlock buttons on the front and a panic button on the back. This remote has FCC ID PLNHM-T002 and a Hyundai part number of 95411-0Wxxx. See the new-body-style remote – Remotes Unlimited part 979-1979 – at this link.
Please note that these remotes are not interchangeable and that 2006 Hyundai Santa Fe vehicles require a scan tool to program the system to add a new remote.