These bits activate when the corresponding Software Limit is activated. The Software Limits are inactive and disabled by default. When these bits are active, motion is inhibited from continuing in that direction (i.e. when the positive limit is hit, motion cannot proceed in the positive direction, only in the negative).
1) Disable the Software Limits with the LS command.
2) Check the starting zero position to make sure it is correct. The Software Limit positions are based upon the zero location.