The DM always makes the Proficiency Check for this proficiency.
If the check is successful, it means that the character has
determined the proper direction. If the check is unsuccessful but
greater than 1, the roll is off by up to 90 degrees to the left or the
right (DM’s decision). If the Proficiency Check is a 1, the character
determines a direction that is exactly opposite of the true
direction.

* This proficiency requires a d20 roll for success (Proficiency Check) each time it is used.
 

Direction Sense (1, WIS, -1) (WSG): Any group containing at least one character
with proficiency in direction sense has a reduced chance of becoming
lost or disoriented in any type of terrain. A Proficiency Check is required whenever the DM determines
that the group has a chance of becoming lost or disoriented, and
this die roll is always made by the DM in secret. The
check is made with a die roll modifier of +4 if the group is in total
darkness, or +2 in conditions of partial darkness. Success indicates
that the group has no chance of straying from its intended
path or losing its sense of direction. If the check is unsuccessful
but less than 20, the character has incorrectly sensed direction
by an error of 90 degrees to the left or right (DM’s decision). If the
Proficiency Check is a 20, the character determines a direction
that is exactly the opposite of the intended path.
If a group includes more than one character with this proficiency,
the Dungeon Master should make a Proficiency Check
for each such character. If each character determines that a different
direction is the one desired, then the party will have to decide
among themselves which character’s sense is to be trusted.
If more than one character makes the same determination, it is
likely that both of their Proficiency Checks have succeeded -
but it is also possible that they have both made the same error.