2002 Prius loses power steering occasionally - no vibration

Those are surely transistors (given away by their three leads, and the T designation silk-screened on the board, and the likelihood that the ECU needs a bridge of honkin' transistors to drive the motor).

I did build an amplifier way back in the day where, in order to get a temperature compensation diode matched as well as possible to the output transistors, it actually was another one of the same transistors, mounted on the same heat sink, and converted to a diode by clipping one lead off.

 

Hello. New to the forum. Have a 2002 prius, ~175k miles. Wife just sent me a picture of "red triangle exclamation" on the dash and "warning PS" on the screen. First time its happened in the 9 months that I've owned it. My wife didn't state any shaking but did lose power steering pulling into our driveway (right U-turn). Been researching for hours here and elsewhere.

If it is the PS ECU, would a used replacement require reprogramming? If so, can I or any repair shop do that?

Figured I'd start there if problem persists. Cheap and easy to get to. Ive worked on cars before but I am not an expert by any means so, if you are, feel free to tell me if thats not a good idea. Thanks in advance.

 

Kyle in Seattle (I guess it rains there a lot.... and that's important),
Best place to start is to find (or make) a friend that has a TechStream scanner, and pull the codes from the problem Prius.
It's a coin toss as to whether it's the sensors in the rack-and-pinion assembly (which are moisture sensitive) or (in my opinion, somewhat less likely) a failing PS ECU. Only more data can change the odds.

Do let us know how the problem resolves....

 

I pulled the codes. None are related to this problem. They are catalytic converter related since mine was stolen a year or so ago and they ripped out all my wires and whatnot.

Does that give you any ideas? Thank you.