While it is never seen, X.A.N.A. always uses this code to activate towers on Lyoko. It is quite possible that the red lines inside Lyoko's wires are X.A.N.A. sending the code to the tower to activate it or seize control of it (in the case of the tower being under Jeremie's control). If the code is implemented into an ordinary tower, X.A.N.A. will have complete control over it. If the code is put into a Way Tower, then X.A.N.A. has complete control of a sector and almost immediately, it will always delete the sector to stop the Lyoko Warriors from accessing Sector Five via the Transport Orb.
The first time we actually see the code used when X.A.N.A. uses it in Season 3 to destroy the sectors of Lyoko. However, X.A.N.A. cannot input the code directly into way towers, nor do its monsters have the ability to enter towers. When X.A.N.A. plots to destroy a sector, it needs a virtual person under its control with the Annex Program to do the task. It needs to possess Aelita with the Scyphozoa and use her to do it.
Whenever this code is entered, all towers and ground quickly vanish until there is nothing left of the sector as X.A.N.A. will often delete the sector as his only act of control over it. Even monsters end up falling into the Digital Sea several times throughout the series, simply because they have nowhere to run. The Lyoko Warriors must be devirtualized either manually or by themselves before they can suffer this fate.
In Lab Rat, this code was once used by X.A.N.A. William to sever the Skidbladnir's connection to the tower on the Forest Replika. Severing this connection instantly teleported all translated people back to the Skid. It is also shown in Sabotage that anyone with Source Codes or access to the Annex Program, can voluntarily enter the code into a tower, even when they are not under X.A.N.A.'s control.
Times When Used