Error code problem

The code points toward either a leak in the hydraulic system for the rear brakes or a bad actuator. And if you have rear disc brakes it could be a problem with a disc. I first would check the physical condition of the brakes, then look in to replacing the actuator which is quite expensive. Good luck.

Edit: Here's a thread about DIY: Brake Actuator Replacement | PriusChat

 

Learn to use the search function w/in Prius Chat or an Internet search engine (Goolge, Yahoo, MSN, etc).


Many times, the help you seek (especially with a known error code) has already been asked and fixed.


You should get the factory service manual from Toyota's TIS (Tecnical Information System). https://techinfo.toyota.com/techInfoPortal/appmanager/t3/ti?_nfpb=true&_pageLabel=ti_home_page
It has all the codes and the trouble shooting you would have to go through, electrical diagrams, and more. Way more and a lot better information than Haynes/Chilton repair books.
$15USD for a 2 business day subscription; the site will likely require a USA billing address and credit card. Hopefully you have family/friends in the US.