Honda Pioneer 1000 2017 Owner's Manual page 114

This mode supplies power to the rear wheels only. This mode is for
driving on turf.
This mode supplies power to the rear wheels, and locks the rear
differential. This mode is best for surfaces that provide good
traction.
This mode supplies power to the front and rear wheels, and locks the
rear differential.
Steering will require slightly more effort than with 2WD. This mode
is recommended for driving on surfaces that provide relatively poor
traction.
This mode supplies power to the front and rear wheels, and locks the
rear and front differential.
As a result, steering will require extra space and effort. Select this
mode to maximize available traction.
I
This mode supplies power to the front and rear wheels, and locks the
rear differential. In addition, Brake Traction Control System (BTCS)
will work to enhance vehicle stability in slippery conditions.
Brake Traction Control System (BTCS):
BTCS applies the front brake in slippery conditions to help prevent
loss of traction due to wheel spin when applying the accelerator
pedal.
When applying the brake while BTCS is operating, the brake pedal
will have a flutter feel. This is normal.
Before using the drive mode select lever to change from one mode
to another, be sure the vehicle is stopped and the engine is idling.
See page 44 for additional information.