You cannot remove cheats from Need for Speed Carbon on Xbox 360. Cheats are baked into the game code—no menu, file, or setting disables them.
Entered at Main Menu → Options → Cheats (case-insensitive):
unlockallthings – All cars, parts, crew.gimmethegto – 1965 GTO.carbonrocks – $100,000.slideways – Drift tires.Once entered, they're permanent for that save. Only fix: new save.