Some comments, again, specific to the 2001-2003 Prius. The certain symptom is a distinct hesitation in acceleration and sometimes speed holding. In some cases a DTC is set. Toyota apparently replaced a large number of these, and the post-warranty owners did not all enjoy the retail price

DIY is entirely possible, but if you make a mistake there is little alternative to buying a new one. Also your car won't function in the interim. Building a simple jig to keep all the parts aligned when the sealing-up epoxy is setting is a key point.

Probably somewhere there is a failed unit where the potentiometer traces have fallen off. Such a thing would not be fixable.

By the time Bob does his 10th one, I reckon the labor time will be down to 20 minutes

DAS