I have recently noticed that if I quickly turn the steering on my Prius from lock to lock (such as a quick and tight 3 point turn in the road) the steering feels like it's running out of power on and off. It's difficult to describe but it feels like the power isn't enough to quickly turn the wheel from lock to lock. Say you reverse the car slightly whilst turning from lock to lock and then select drive and then turn lock to lock again, the steering goes light, heavy, light, heavy etc. Is this normal under these circumstances or is it a problem developing? Once you get going it's all normal again. I had the car in some months ago for a steering column issue where something was replaced and the steering tightened up nicely. It is now starting to have a teeny bit of play in it again and then the issue quoted above. Just thought I'd run it by you guys before I contact the dealers. I'm not working for a few days so no worries there. Advice appreciated.
Grumpy, I tried that on mine and the steering maybe feels a little stiffer when I turn the wheel as fast as I can, but the effort is even with no on-off feeling at all. On the US Gen III Prius, Models II-IV have a brush type electric motor for the PS and the model V has a brushless motor. The V also has quicker steering. Which system do you have? I have a model II which has the brush type motor. Some countries use the brushless motor in all the models
I have no idea. I have the base model Prius but I think the specs are similar to either your 4 or 5 model. I'm guessing having the RHD Prius that the UK version will be based heavily on the Japanese home market model so I guess I have the same motors as they do. The problem only happens if trying a fast turn as quoted above rather than if you just sit stationary and turn it quickly from lock to lock, where no problems occurs.
Since you have already had problems with it once taking it in and having them check it over might be a good idea. Something in the steering mechanism might be binding up and the steering motor is having trouble providing enough torque to turn it.