Question about a cheat code for the game "Mercenaries"?

[Kung Fu Imposter]

I have regular xbox and i own the game mercenaries. There is a cheat that enables you to play as and Allied pilot without a helemt. You need to bring a car to the Russian Mafia garage and put the code in while you are in there. I've tried several times with different versions of the codes but i can't get it. Why doesn't it work?

 

[Tj K]

code doesn't work