Power steering (?) "chatter"

I'll try to revive this thread that no one responded to because I'm having the same trouble, only with 2 cars. I've got an 01 with 157,000 miles and I just sold an identical 01 with 206.000 miles. Both of them are doing the same thing as listed above. It's not every day, but just "sometimes". I've noticed it when I first crank the car or after driving but when turning the wheel. It literally shakes the steering wheel so hard you can really feel it. Not sure if it could be a piece of debris in the steering motor or valve or what it could be making it chatter. No lights and no codes found with the mini vci.

 

I know the first generation Prius had a recall for the pinions, but I don't think that solves the problem. My 03 Prius started doing that. I shook so hard I could barely control the wheel and a week later I started getting a warning triangle and the "ps" symbol for power steering. Now here's the kicker, while driving on a highway the warning popped up out of no where and I lost all power steering. It took all my strength to maneuver the car to safety. Once turned off and on I regained power steering but only for a short time. My mechanic tell me the RAC needs replacement which I'm guessing you will be having the same issue very soon. I've made complaints with national highway safety and with Toyota manufacturers. I believe the recall with the pinions is a deeper issue. If you google complaints for first generation Prius and power steering, you will see everyone say the same thing. Even after they had the recall done, the problem persisted and the majority of them have had to replace the RAC. Some of the cars weren't even high mileage.

I suggest you have the car looked at and make a complaint as well. You don't want to be like me doing 70 on a freeway and lose all steering.

 

2001 to 2003 Prius was susceptible to two different steering issues, which should not be confused with each other.

In one, the nuts at the bottom of the rack pinion could work loose, resulting in a condition where the gear binds up when you try to turn left. There was a recall for that.

In the other, the torque sensor built into the steering rack grows electrically noisy with age, the steering amplifier amplifies the noise and sends it to the assist motor, which shakes the wheel. That was not handled by a recall, but there was a greatly extended warranty for it right through December of 2013, twelve years past the first affected model year.

It is common that you don't notice the steering shake except at low speeds. The normal behavior of the steering amplifier is to cut back the assist at higher speeds, so it makes very little difference to your steering except in, say, parking lots. The shake is disconcerting. Holding the wheel more firmly helps (doesn't have to be a death grip, just have the weight of your arms be part of the oscillating system).

The steering computer has only so much patience for noisy input, and after seeing too much of it, it will cancel all assist, which leaves you with manual steering. Again, you only notice this at low speeds. Steering is always easy at cruising speed, but parking a Prius with unassisted steering is good upper-body work. In the early stages, it will only be on pretty long trips that the computer counts up enough noise to cut out. As the torque sensor gets noisier, that will happen on shorter and shorter trips. Turning the ignition off and back on will give you assist again, until the next time the computer gets fed up. If you get tired of the shaking (and would like to get ripped), you can unplug the torque sensor at the steering computer and have manual steering all the time.

There are lots and lots of threads in this forum about the condition, and what options you have for correcting it.

-Chap

 

So does it seem as if my only options is to dish out the $3300 for the repair? I didn't come into ownership of the car until it was too late to know about the warranty. 2 years after pinions replaced, steering has gone to shit. Even after the replacement, the steering wheel still shook violently.

 

I think I mentioned those are two unrelated issues, right? Your shaking comes from the torque sensor issue. Replacing the nuts on the pinion shaft was about the steering-gets-tight-when-turning-left issue, nothing to do with the torque sensor one way or another.

On this model the torque sensor is built into the steering rack and Toyota does not sell it separately, so the only official repair is to replace the rack. The one from Toyota is pricey. Because this issue has been so extensively discussed over the years in this forum, you should have no trouble finding the details on other options. I believe Cardone sells a remanufactured rack. I think I read more recently that another supplier entered the ring. Bob Wilson has some ideas about tin whiskers, cheap enough to be worth trying whether or not they help. There is a thread explaining disassembly of the rack to get the torque sensor out and clean it. In principle that's no different from cleaning up the other noise-prone variable-resistance sensors on the car, like the ones on the heater servos, the only difference being that you can have the heater servo in the palm of your hand in about two minutes with one screwdriver, but getting the steering rack out is much more labor intensive.

-Chap