For Pokemon D/P, it should work automatically.
For Pokemon Pt, you need to press the R+B buttons.
No, you cannot walk through walls without an Action Replay. You are not allowed to walk through walls in any video game without cheating, so the only way to do that is by using the Action Replay.
ACTION REPLAY.
there is already codes for diamond and pearl to walk through walls if you don't have them then update your action replay. There is no code to walk through walls for platinum.
you use an action replay use an action replay
no you can't do that wiyhout an action replay
action replay
yes there is.
you have to keep action replay in on most cheats. Some you just have to put the check mark.
the only way you can go through walls is if you have an action replay so if you want to get a legendary Pokemon that you can't find like sheyman then you have to have an action replay
you just get a action replay and enter a code,look up the code
if you want to walk through walls yes
get a action replay