Micro Machines.

 No.  Code  Effect
   1  REHA-A60N  Infinite lives in 4-man race
   2  AEBT-AAHL  Start with 1 life in 4-man race
   3  AJBT-AAHL  Start with 2 lives in 4-man race
   4  ATBT-AAHL  Start with 4 lives in 4-man race
   5  AYBT-AAHL  Start with 5 lives in 4-man race
   6  BJBT-AAHL  Start with 10 lives in 4-man race
   7  CTBT-AAHL  Start with 20 lives in 4-man race

Codes 8 Thru 14 apply to Head-to-Head races ONLY.

   8  REET-A6Y6  Infinite lives in head-to-head race
   9  AEEA-AAAW  Start with 1 life in head-to-head race
 10  AJEA-AAAW  Start with 2 lives in head-to-head race
 11  ATEA-AAAW  Start with 4 lives in head-to-head race
 12  AYEA-AAAW  Start with 5 lives in head-to-head race
 13  BJEA-AAAW  Start with 10 lives in head-to-head race
 14  CTEA-AAAW  Start with 20 lives in head-to-head race

Codes 15 Thru 17 only work after the initial qualifying race.

 15  AEFT-AAH4  You qualify for next race only if you win
 16  ANFT-AAH4  You qualify for next race if you get 3rd or better
 17  ATFT-AAH4  You always qualify for next race
 18  AEGT-AAC8  You get to time trial every time you win 1 race
 19  AJGT-AAC8  You get to time trial every time you win 2 races
 20  ATGT-AAC8  You get to time trial every time you win 5 races
 21  AYGT-AAC8  You get to time trial every time you win 6 races
 22  A6GT-AAC8  You get to time trial every time you win 8 races
 23  BJGT-AAC8  You get to time trial every time you win 11 races
 24  RYXT-A61R  Infinite time in Ruff Trux time trial
 25  XFYA-BXFC + JBYA-AE0C  100 seconds to get through Ruff Trux time trial
 26  ABYA-BBFC + JBYA-AE0C  90 seconds to get through Ruff Trux time trial
 27  ABYA-AA7C + JBYA-AE0C    60 seconds to get through Ruff Trux time trial
 28  ABYA-BAPC + JBYA-AE0C  30 seconds to get through Ruff Trux time trial
 29  ABYA-AAPC + JBYA-AE0C  20 seconds to get through Ruff Trux time trial
With Codes 30 Thru 33, the extra lives will not show, but you will have them!
 30  AJHA-AA5W  Winning Ruff Trux time trial worth 0 extra lives
 31  SAHA-BJXW  Winning Ruff Trux time trial worth 2 extra lives
 32  SAHA-BYXW  Winning Ruff Trux time trial worth 5 extra lives
 33  SAHA-BAXW  Winning Ruff Trux time trial worth 8 extra lives
 34  AKHT-AAH0  Each race lasts 1 lap
 35  APHT-AAH0  Each race lasts 2 laps
 36  AZHT-AAH0  Each race lasts 4 laps
 37  A3HT-AAH0  Each race lasts 5 laps
 38  BBHT-AAH0  Each race lasts 7 laps

Codes 39 Thru 42 may mess up the lap counter graphics.

 39  BPHT-AAH0  Each race lasts 10 laps
 40  CZHT-AAH0  Each race lasts 20 laps
 41  GPHT-AAH0  Each race lasts 50 laps
 42  NZHT-AAH0  Each race lasts 100 laps
 43  BA7T-AA34  Each race lasts infinite laps--only on head-to-head races