Do Cheats Disable Achievements in GTA IV? Yes—Permanently for That Save

Yes. Activating any cheat code in Grand Theft Auto IV (PC, Xbox 360, PS3) **permanently disables achievements/trophies for that save file.**

The game warns you when entering a cheat. Once saved, that file cannot earn achievements even if cheats aren't used again. To hunt 100% completion or specific achievements, use a clean save or start a new game without cheats.