If you want Niko to dial a number, including cheat codes, press the directional button upwards twice, and you will get the blank screen ready for number input. Use the directional button to go to the numbers you require, pressing "X" to select each number, then select the telephone icon on the left hand side to ring that number.
To enter cheat codes:
Enter cheats during normal gameplay. Find the cheat you want to enter, activate Niko's cell phone as above and put in the numbers using the directional buttons. When the cheat is entered a message will be seen saying "Cheat Activated". Not always a good idea to save the game when cheats are used though.
During game-play type in the speech box a cheat, For example: JUMPJET OHDUDE BRINGITON
Press up on the D-pad twice. Then you can enter the number for the cheat and press call to activate it.
Enter the health cheat
You have to enter the Dodo cheat.
You have to look up GTA 4 cheat codes then enter the number on your phone in the game p.s. (Hope this helped)
RIPAZHAcheats.
You have to type them in either while paused or playing. However you need to type them very quickly.
all you do is enter the cheat another time.
there is none, unless your talking about the cheat section on gta4, all you have to do is enter a cheat once and it will be saved on your phone.
You just type in the desired cheat during gameplay.
You enter in on the main screen, "DoItYourself"
You just simply enter them in using the controller (PS2 X-box) or keyboard (pc) while playing the game and not paused.