For the MC18 R5K this is what the manual says:

Throttle sensor inspection:
measure 16P coupler Bu/G and Y/R resistance. Std resistance (20deg C): 4-6K ohm
measure resistance between Y/Bu & Bu/G when throttle is fully closed to fully open and if each resistance value is exceeded then it is normal.
Std resistance (20deg C) Fully closed: 0-1.5K ohm (throttle stop screw loosen safely). Fully open: 4-6K ohm. When value becomes large, remove throtthle sensor 3P coupler connection and perform the above inspection at both sides of the sensor coupler terminals. If measured value is inside standard resistance value, then correct wire harness or replace it. If measure value is larger than the standard value then replace throttle sensor & sensor stay assy, joint, throttle shaft & throttle link arm as a set.

So I would say measure the resistance between the Y/Bu & Bu/G and adjust until you are within the correct range. This is assuming that the TPS work the same on all models, but it would help if someone could confirm this.

Cheers