My car threw two dash messages- hybrid system malfunction and pre-collision fault. was not drivable. I used Carista and codes were battery voltage isolation and "manufacturer specific" code. Dr. Prius showed no codes. Battery was damaged beyond repair- shorted due to mouse nest inside the traction battery. The battery is a total loss. Fortunately, our comprehensive policy will cover the cost of the repair. So, word to the wise...check your car insurance policy to see if this type of damage is covered. Normal wear and tear is not covered. I'm thinking the other code may have been thrown due to high voltage leakage to chassis (caused by mouses). Another cause of this is water leakage into the battery area from ingress from the chassis. Not much to see- just a bunch of sound insulation wadded inside the battery case.
It showed you the actual codes, right? You should include those in posts. We don't as much need what Carista thinks they mean; looking in the repair manual is better for that, anyway. Toyota Service Information and Where To Find It | PriusChat
I don't know what Carissa is but it's not techstream. Mechanics pay more for quality tools because they're worth it. Get techstream.