Power steering sometimes doesn’t unlock and is stiff

What do you mean by "the steering unlocking"? There is no steering lock on a Gen 2, so I'm wondering if you mean that the power steering is not working causing the steering to be very heavy.

Are there any warning lights on the dash? If so, have you had the DTCs codes read?

 

What are you using to scan the car? Many budget devices can only talk to the ECM (engine computer) - maybe a few other systems. You need a fully capable tool to scan the 15-16 systems on a Gen2 Prius.

Here's a thread that reviews several different apps and devices. I would start with a complete scan of the car.

I would expect the power steering warning light to be on, and would be very surprised if you lost boost without some codes set somewhere.

Posted via the PriusChat mobile app.

 

I may have a similar problem. My car has heavy steering, compared to the other 2 gen 2s in the family. Also, going around a corner in the other 2 if you let go of the steering wheel the car automatically unwinds and the car goes straight. This should happen, it is due to the suspension geometry design like all cars. So in my car you take a corner and if you let go of the wheel it will just go in a circle. I am checking the suspension now, right strut rotates freely with the car in the air and steering tie rod off. Other side knuckle has not let go of the tie rod but a soaking overnight and some heat today should fix it. Open to other things to look at, the car failed state inspection so this is in the must fix category.

 

Sounds like your rack and pinion has a o-ring go bad and is leaking fluid to the other side of the piston.
Had this happen to my Acura. Took it to a reputable shop and they repaired it in one hour and $125.00.

 

The Prius has electric power assist so no fluid to leak. It is more likely something to do with the power steering motor.

 

Oops. The link didn't show up on my last post.
https://priuschat.com/index.php?posts/3290690

Posted via the PriusChat mobile app.