Originally Posted by jlarroulet

"pre chequeado" is consistent with a T-48 online check-in (as per TSA rules, LAN is not allowed to issue a boarding pass more than 24 hours prior to departure time for international flights originating in the US)
The only difference between "pre-chequeado/pre checked-in" and "chequeado/checked-in" is in fact the boarding pass issuance.

If you go back to LAN's website (after becoming pre-chequeado) within the T-24 hour window, the website should issue you your boarding pass (if it doesn't, it means they have a bug that needs fixing.. although they probably don't know about it yet)