Hopefully someone can help me trouble shoot my 2003 Prius. I was rolling to a stop sign on a country road when it felt like I lost my brakes out of the blue and the red BRAKE light came on. I think I still had the rear drum brakes because I was able to come to a stop. Once stopped, I tried to drive but the car was dead. All the electronics were on but neither the gas nor electric motor run or provide power to the wheels. When I turn the key off and on again all the accessories come on but the car doesn't start. Any insight what is wrong? Will the car prevent itself from being driven if there's a brake failure? Car has 386k miles. Was hoping she'd make it another year to 400k. Thanks in advance and feel free to move this thread to the Gen 1 forum if there is one!
The best starting point is to have error codes read from the computer. Any generic code reader won't do (such as those used at big box auto parts stores). It has to be one that will read Toyota specific codes to all systems. The Toyota system for that is called "techstream" (you can search for that here) but many other code readers are capable of reading all of your error codes. For now I'll just say that it is likely that some failure occurred that was sufficient for the programming engineers to decide that the car isn't safe to drive with whatever the failure was. So the computer "purposely" makes the car undriveable. In any case, you can't even get started without the error codes.
Lots of trouble codes in Gen 1, including those for the brake system, can be read with no scan tool at all, just by applying a short piece of wire between two pins at the diagnostic port, and counting blinks of dash lights. This I'll often recommend as step one (or step zero!) whenever there are warning lights, because you can do it right away, any time, anywhere, no getting to a dealer or scrounging up a code reader. Other threads here can be searched up for the procedure. But be aware not all codes can be blinked out that way. You'll know what the brake system codes are, if any. If there are hybrid system codes, you won't know what they are (but you will know you have some, because the brake system code C1259 is set when you do, and you'll see that). It's a start, anyway.
Got it figured out and it had nothing to do with the brakes. The car must have died coming to the stop sign and I lost power brakes but given the nature of the car shutting off anyways when coasting to a stop I didn't realize that it was off off. It was the drive motor invertor water pump. It blew the fuse so wasn't sending any codes initially. Got a new water pump in there and back on the road again! Not an expensive fix thankfully.
