Access Password Screen:
Goto Option and choose Game Status. Then press and hold the following:
L1+R1

Enter a code below as a password:

Killer Missiles:
BLAST_FIRE

More Speed:
MORE_SPEED

Increase Attack:
UNDER_FIRE

Quick Shot:
RAPID_FIRE

Play Alone(arcade mode):
HOME_ALONE

Zero Gravity Mode:
NO_GRAVITY

Big-Wheel Mode:
GO_MONSTER

View FMVs:
LONG_MOVIE

Wheel Attach. Off:
DRIVE_ONLY

Hi-Rider Cars:
JACK_IT_UP

Super Ramming:
GO_RAMMING

Random Action:
QUICK_PLAY

Slo-Mo Mode:
GO_SLOW_MO

Play Same Car as Opponent(multi mode only):
MIXES_CARS