How can I program a Toyota pallet jack to have an increased top speed and a decreased top speed?

I train new people at my work and many have never been on a walkie-rider pallet jack before. I would like to decrease the top speed for them (for safety reasons). They usually spend 2 weeks with me and then I'm back to doing my job and would like to increase the speed back up. The model Toyota I'm using is 8HBE30. It has a keypad on the handle, so I'm hoping it's something as simple as punching in a code.