What is the cheat code for orange island event in Pokemon fire red?

There is no cheat code for the Orange Islands event in Pokémon FireRed.

The Orange Islands event is not part of the original Pokémon Red and Blue games and was only added in Pokémon Yellow. This means that it is not included in Pokémon FireRed, a remake of the original Red and Blue versions.

You cannot participate in the Orange Islands event in Pokémon FireRed.