Load your profile then select the "Codebook" option in the bottom right corner. Enter one of the following passwords to activate the corresponding cheat function.

Effect	Password
10 Canisters	NERF
Unlimited Ammo cheat	DART
Cerberus CS-12	DUDE
Crusher SAD-G	RUSH
Golithan UB-1	ROCK
Hammerhead GL-1	PONG
Hydra SG-7	WIDE
Icarus HM-7	DOOM
Longshot CS-6	IDOL
Longstrike CS-6	PING
Recon CS-6	DIRT
SemperFire RF-100	FLEX
Spartan NCS-12	ICON
Vulcan EBF-25	LOTS