When a throttle error has occurred the following procedure is followed to test the throttle pot. 

Take an ohm reading between 1 and 2.  Take an ohm reading between 2 and 3.  Both readings should be equal.

If they are not equal the potentiometer has to be centered.                                

Loosen the Allen screws (#1) slightly.  There should be one on each side. Adjust the potentiometer (#2) slightly in one direction.  Repeat the ohm readings.  If the difference has decreased keep adjusting in that direction until the readings are equal.  If the difference has increased, adjust in the other direction. Tighten the two Allen screws.

If after the unit is adjusted there is still a throttle error code then the throttle has to be replaced.

 Throttle pot testing

        & adjusting.