Instructions
Choose a cheat code you wish to enter. You can find plenty of cheat codes for "Grand Theft Auto 4." You can summon a wide variety of cars, helicopters, motorcycles and boats at your pleasure. You can also give yourself lots of weapons and full health and body armor.
Pull out your cell phone. Press down on the D-pad to pull your phone out. Enter in the proper phone number for the cheat code you wish to enter. For example, 625-555-0100, will spawn a motorcycle.
Press "A". This will dial the number and enter your mod into the game. You can then enter another cheat code if you wish.