I have a 2005 Toyota Prius, 200k miles

After getting the Master Warning red triangle with exclamation point light

accompanied with the Brake system light, I thus later took it to the dealer.

Originally,
The car would not start again after returning to my driveway after just entering the street when this all happened.

I left the vehicle there for 1 month after working out of town.

Now after returning, I unhooked the 12v battery, gave it some time.

Then I rehooked the 12v battery to see if the I could start the Prius.

In order to drive it to the dealer to save towing costs. It started and soon afterward
I got the same two warning lights, thus carefully drove it off to the dealer.

There appeared to be no obvious problems with the braking system and other aspects of the car did very well on this drive to the maintenance dept.

I did read up on the Parking brake being on (causing the warning lights) while trying to drive the Prius, so I ensured the Parking Brake was off. Only other thought on this; could the Parking brake which I had always set, not be signaling off to the car system, despite the fact that I had the Parking brake off?

The maintenance dept. from my local Toyota Dealer first called after 4-5 hours to inform me that they determined that there was a short in the system, and that they needed me to approve for the mechanic to do approximate 5 more hours of work to find the source of the short. This at $153 per hour with a new additional diagnostic cost of around $765 to determine the source of the short. With this call the dealer svc rep said that once this was done it could be one of a number of problems, including having to replace the Prius Hybrid battery system.

My question is coming, but this car had a new hybrid battery system installed by the a different Toyota dealer back in March2013, at that time it was only weeks after it had been rear ended, not entirely badly, needed outside back end repair, yet was at 105k miles just outside the warranty given at time of purchase in OCT2005.

This new problem is now just after second hybrid battery warranty of 8yrs or 100k.

I have become suspicious that Toyota has programmed these problems to arise in short time after the warranties expire?

Should I pay the Dealer $765 to determine the source of the short? which will eventually lead to additional repairs up to $3k to replace the hybrid battery sys as indicated by the maintenance svc rep?

Or should I just go straight to an off market reputable hybrid battery replacement company whereby they are advertising in the range of $1100.

I am leaning to take the off market option, but my thoughts are if this option is exercised will I then still have the so-called electrical short in the system?

Your feedback is greatly appreciated.

Patrick