car wasnt working and mechanic deleted something electronically and it worked again. explanation????

Welcome to PriusChat!!

Generally speaking, when there are warning lights being displayed on the dash, there will be OBD2 codes stored in the computers (ECUs)

Did the mechanic(?) record or write done the OBD2 codes (DTCs) before deleting them? (always a good idea)

FYI : you're being moderated until you've posted 5 times.

 

Sometimes clearing a code will allow the car to go back to operating normally. It is a temporary fix and may not work long, until the code is rethrown. Meaning you have to actually repair the problem that's occuring.

 

THIS.
If that is ALL he did, the original problem is still there.

 

You probably have a bad hybrid battery and it is throwing a ground fault code.
That will put the car into limp mode meaning no contribution of the hybrid battery then on engine only and car then has no power.