The following are known GameShark Codes for R4: Ridge Racer Type 4 on Sony Playstation (PS1).
These codes were also known as Action Replay Codes and in most cases will work on both devices.

These codes are for the Japanese version of the game.

• Always 1st/Drive Thru Cars (Press Select)
  D00F381A 0100
  800ABE66 0003
  Note: You will only race for half a lap or so and you must activate it before the cars in front of you enter second lap.
• Instant Win (Press X & Select)
  D00F381A 0140
  800ABE66 000C
  Note: On the last race (shooting hoops course) you still need to race for a short distance.