Enter the following cheats at the "Code Entry" screen under the Secrets option. Note: Each game disc has one of a few random "access codes". Only cheats that are made for the access code that matches your own disc's access code will work for you.

Access code 8426

Code - Effect

NYOOTWCF - All cars and championships except 3 bonus Championships
NYOOTWCF - All cars and 3 bonus Championships
LLNWUGXT - Double engine power for all cars
DBXLYJUU - Swap Front wheel drive cars to rear wheel drive
GFNPIDBY - No car damage
WVUMRQMJ - Unlock all cut scenes

Access code 9535

Code - Effect

LRCHBQJ - All cars and championships except 3 bonus Championships
GXZCDRMQ - All cars and 3 bonus Championships
LBHXBAAA - Double engine power for all cars
DEPEXGAA - Swap Front wheel drive cars to rear wheel drive
ILKGJIGV: No car damage
RQPJZZOU - Unlock all cut scenes

Access code 7018

Code - Effect

TSCNJDRS: All cars and championships except 3 bonus Championships
UDFCGFCM: All cars and 3 bonus Championships.
NULPUXTH: Double engine power for all cars (XBOX) or to increase the overall speed of your car (PC)
ZRIGBHBY: Swap Front wheel drive cars to rear wheel drive.
XGAAYRSP: No car damage.
BAAAQEPU: Unlock all cut scenes.

Access code 4707

Code - Effect

KTQMDZYI: All cars and championships except 3 bonus Championships
VRWZWIIE: All cars and 3 bonus Championships.
NYLLXYMT: Double engine power for all cars (XBOX) or to increase the overall speed of your car (PC)
OYKAKZJQ: Swap Front wheel drive cars to rear wheel drive.
FRKBNMUE: No car damage.
HZOLMXZN: Unlock all cut scenes.

Access code 0798

Code - Effect

AFRDKGIT: All cars and championships except 3 bonus Championships
EJEUBCQP: All cars and 3 bonus Championships.
CWVFUETA: Double engine power for all cars (XBOX) or to increase the overall speed of your car (PC)
MNEYYXVK: Swap Front wheel drive cars to rear wheel drive.
EZXYFQWV: No car damage.

Access code 3803

Code - Effect

FRKBPWYY: All cars and championships except 3 bonus Championships
HZOLAQEZ: All cars and 3 bonus Championships.
NYSGFPXE: Double engine power for all cars (XBOX) or to increase the overall speed of your car (PC)
VJMEHNZR: Swap Front wheel drive cars to rear wheel drive.
KTQMNLEY: No car damage.
VRWZMNGW: Unlock all cut scenes.