Enter the following during gameplay.

Tier 1 weapons :
Press R1, R2, L1, R2, Left, Down, Right, Up, Left, Down, Right, Up. This will unlock the weak weapons.

Tier 2 weapons:
Press R1, R2, L1, R2, Left, Down, Right, Up, Left, Down, Down, Left. This will unlock the medium weapons.

Tier 3 weapons:
Press R1, R2, L1, R2, Left, Down, Right, Up, Left, Down, Down, Down. This will unlock the powerful weapons.

Respect upgrade:
Press R1, R2, L1, X, Left, Down, Right, Up.

Bounty on your head:
Press Down, Up, Up, Up, X, R2, R1, L2, L2.

Armor, health, money, and street creds:
Press R1, R2, L1, X, Left, Down, Right, Up, Left, Down, Right, Up.

$250,000:
Press R1, R2, L1, X, Left, Down, Right, Up, Left, Down, Right, Up.

Raise wanted level:
Press R1, R1, Circle, R2, Left, Right, Left, Right, Left, Right.

Lower wanted level:
Press R1, R1, Circle, R2, Up, Down, Up, Down, Up, Down.

Perfect handling:
Press Triangle, R1, R1, Left, R1, L1, R2, L1. Press L3 to jump in a car.

Aggressive traffic:
Press R2, Circle, R1, L2, Left, R1, L1, R2, L2.

Faster cars:
Press Right, R1, Up, L2, L2, Left, R1, L1, R1, R1.

Drive on water:
Press Right, R2, Circle, R1, L2, Square, R1, R2.

Destroy cars:
Press R2, L2, R1, L1, L2, R2, Square, Triangle, Circle, Triangle, L2, L1.

Flying boats:
Press R2, Circle, Up, L1, Right, R1, Right, Up, Square, Triangle.

Spawn Rhino tank:
Press Circle, Circle, L1, Circle, Circle, Circle, L1, L2, R1, Triangle, Circle, Triangle.

Spawn Bloodring Banger:
Press Down, R1, Circle, L2, L2, X, R1, L1, Left, Left.

Spawn Ranger:
Press Up, Right, Right, L1, Right, Up, Square, L2.

Spawn Hotring Racer 1:
Press R1, Circle, R2, Right, L1, L2, X, X, Square, R1.

Spawn Hotring Racer 2:
Press R2, L1, Circle, Right, L1, R1, Right, Up, Circle, R2.

Spawn Romero:
Press Down, R2, Down, R1, L2, Left, R1, L1, Left, Right.

Spawn Stretch:
Press R2, Up, L2, Left, Left, R1, L1, Circle, Right.

Spawn Trashmaster:
Press Circle, R1, Circle, R1, Left, Left, R1, L1, Circle, Right.

Spawn Caddy:
Press Circle, L1, Up, R1, L2, X, R1, L1, Circle, X.

Pedestrians riot:
Press Down, Left, Up, Left, X, R2, R1, L2, L1.

Pedestrians have weapons:
Press R2, R1, X, Triangle, X, Triangle, Up, Down.

Slow motion:
Press Triangle, Up, Right, Down, Square, R2, R1.

Fast motion:
Press Triangle, Up, Right, Down, L2, L1, Square.

Cloudy weather:
Press R2, X, L1, L1, L2, L2, L2, Triangle.

Very cloudy weather:
Press R2, X, L1, L1, L2, L2, L2, Square.

Foggy weather:
Press R2, X, L1, L1, L2, L2, L2, X.

Stormy weather:
Press R2, X, L1, L1, L2, L2, L2, Circle.

Sunny weather:
Press R2, X, L1, L1, L2, L2, L2, Triangle.

Very sunny weather:
Press R2, X, L1, L1, L2, L2, L2, Down.

Commit suicide:
Press Right, L2, Down, R1, Left, Left, R1, L1, L2, L1.

Affectionate women:
Press Circle, X, L1, L1, R2, X, X, Circle, Circle.

Infinite cash:
Sit CJ down at the videogame machine in his hideout and then leave your PS2 for several hours. When you come back you'll have more money.

Headless:
Get a katana and enter a two-player mission. Cut Player One's head off with Player Two, then return to Single-Player mode.

Unlockable vehicles:

Bandito	Get 15 cars for the Import/Export dock
Bloodring Banger	Last a minute in the Bloodring
Bullet	Get all silver awards in driving school
Dune	Beat the score of 25 at the Dirt Ring
FCR-900	Get all silver awards in bike school
Freeway	Get all bronze awards in bike school
HotKnife	Get all gold awards in driving school
Hotring Racer	Get first place in the 8-track
Hydra	Beat the "Vertical Bird" mission
JetMax	Get all gold awards in boat school
Marquis	Get all bronze awards in boat school
Monster Car	Win it by beating 8-track
NRG-500	Get all gold awards at Bike School
Rustler	Get all bronze awards in pilot school
Squallo	Get all silver awards in boat school
Stunt Plane	Get all silver awards in pilot school
Super GT	Get all bronze awards in driving school
Turismo	Get 20 vehicles for the Import/Export dock
Vortex	Get 25 vehicles for the Import/Export dock
Windsor	Get 10 vehicles for the Import/Export dock

Taxi Nitro boosts:
Get 50 fares in a taxi.