Using in-game mods on GTA IV for the PS3 opens up the game and allows you experience new things. GTA IV is a game were you play as a criminal breaking all sorts of laws. A big obstacle to the game is being chased by the police. In the heat of a chase, you can end up breaking more laws that increase your wanted level and therefore the aggressiveness of which the police pursue you. These chases can become intense, but with the police mod, you can immediately get rid of your wanted level and reset the sanity of the game to a nice, even pace.
Press the top button on the directional pad, also known as the "Up" button, on the PS3 controller. This brings up your character's cell phone. In earlier GTA games, you would have had to enter mods by pressing an assortment of buttons during regular game play and this would resort in you firing weapons off and causing more trouble. In GTA IV, you activate all mods through the phone.
Press the "Up" button again. This allows you to start inserting numbers into the phone. For normal game play you would use the analogue stick to move, but for dialling the phone you use the directional pad.
Enter the following phone number into the phone by selecting each number and pressing the "X" button "267-555-0100". The phone dials the number and rings a couple times, then your wanted level disappears.