How do I take my 2003 gmc Yukon out of limp mode

Just drove out of the mountain only
about a hour drive then into the city
as bout a 30 min drive when I got off
the get way with no warning my car
just die would not restart .... It did not
overheat and my battery is still good .
Some reason I belive it went into limp
mode.... How do I fix this I try to undo
the battery did not work ... I test it for
codes none came up .... What do I do