Steering Column Shudders (Vibrates)

We're a Prius family here with two of them. When my daughter leaves for work in the mornings she backs her 2003 Classic out of the garage and while doing so, the steering column begins shuddering while turning either right or left. This does not happen while moving in a straight reverse line. Nor does it happen at anytime after warmup. Driving forward at any speed is smooth and trouble free. A conversation with the service manager at the Toyota Dealer developed the suggestion that the rack and pinion assembly may need repairs. I find this hard to believe since the performance is trouble free after warm up. Has anyone had this problem? Your thoughts or suggestions will be appreciated. Thanks.

This is a known weakness in the NHW11s although usually seen in the 2001-02 models. Sad to say, it take replacement of the whole assembly.

Bob Wilson

Hmm. Thanks Bob for your interest. Sorry to hear that. Well, it drives ok after warmup. We'll just drive it until it quits. Then we'll see exactly what's wrong. That will be better than "let's see if this corrects it kind of repairs".

It is time to trade it in NOW, IMHO. Let the professionals fix it and resell it.
The entire R&P assembly will cost you $$$.

Thanks Ceric. The trouble hasn't been firmly diagnosed yet. Let's hope it isn't the r&p assembly. Could be a hydraulic pump or something.

No hydraulic pump. The steering assist is an electric motor. It knows how much to help (and in which direction) based on a torque sensor. A clever concept but unfortunately includes old-school potentiometers that can become noisy/scratchy like a radio volume control. This leads to substantial confusion for the electric motor.

In this case, it may stay about the same or get worse. Most worst is when the power assist just goes offline. At highway speeds little Prius is easy to steer, but low-speed maneuvers require significant arm strength.

Some potential for safety hazard there, which is what you'd bring up in calling 800-331-4331. Toyota's complaints desk, who may or may not decide to help you buy a new one. Also, tell them that Toyota usta replace them under a warranty enhancement program (which has expired). Those negotiations always require patient persistence.

A new steering assembly installed by Toyota would be about $1600 (perhaps someone can verify this estimate?). Used (warranteed?) prices on car-part.com range from $50 to $250 today. The book says 4 hrs labor, but it would not be the simplest thing for an 'alternative' mechanic to install.

I an uncertain whether the ECU (computer) that manages the thing always needs to be replaced. Those are not exactly cheap either.

That's the story. For 2004 model year they started to make the torque sensor properly, with Hall-effect sensors. No more scratchies.

You never said the mileage on your 2003 Prius, might be a good reference to us all the mileage of your car, when the problem started.

As Bob W indicated in post #2, this has been much less common in the 2003 model year. We all kinda thought that Toyota had improved the potentiometers.

So, an update please?

Would my problem be this--only worse?
I have a Gen I with 180K. The PS error began coming on mid last week and is now on all the time. Though it does start ok, i.e., the steering is smooth as we take a sharp left out the driveway. But once we are on the highway the PS light comes on, stays on and steering on tight bends is an effort.

Sounds like I need to replace the power assist assembly. What is this exactly?
Cheers, John

>This is my 2nd attempt to post to this thread. The first one vanished!

Do I have the same, only worse, problem as described here? I have a Gen I with 180K. The PS light comes on after driving it for a while. Starting off the steering is fine, we have a sharp left to get out the drive way and there's no problem. But once on the road the PS error comes on and it becomes obvious that the steering assist is not functioning. This makes local driving difficult but highway driving is fine.

I have a previous post about this, but briefly, my 2002 started shuddering AFTER I had the steering rack and pinion replaced. Of course, after putting so much into it, and because everything else is so perfect, I'm still driving it and have learned how to avoid the shuddering most of the time. In my car's case, it only happens when turning right quickly at slow speeds. If it gets to the point when it seems like a safety hazard, I'll probably move on, but I still like it better than the newer Prius, which seems so much bigger and more complicated!

If one has the arm strength for it, the 01-03 Prius is diveable without power assist. Parallel parking is a large effort. IMHO the safety hazard aspect arises if the assist goes away when you need to manuever suddenly, and you're probably not expecting that.

Other than paying the high price for 'new from Toyota', used steering assemblies are available but the warranty if any requires negotiation. There was a PC thread long ago about steering sensors being rebuilt but I think it is in the not-fully-confirmed category.

This is my first post in this thread but since the steering shuddering was the reason I found this forum in the first place I thought I would let you know what I think was the problem with the steering in my generation 1 2000 Japanese import Prius. Basically all that has been mentioned previously was happening with my steering (loss of power steering, violent shuddering (even while in park) etc). None of the dealers had any idea why it was vibrating. I bought this vehicle used and the 12v battery was very old and not a battery for a Prius.

The 12v died completely and the car would not start, as the battery was looking pretty sad I replaced it with a new one of the same make and model (standard car 12v (halfords HB154)) and the steering immediately stopped studdering and the power steering began working beautifully. It hasn't studdered again whereas before it was continuously studdering until the power steering failed. I'm going to return the battery and replace it with one that is absolutely appropriate for the prius in the hopes that it will mean this issue will not pop up again.

So, I may be wrong but it seems to me there is a direct coorelation between the power steering and the power output of the 12v battery. Don't ask me what this coorelation is as I have no idea. All I can say is with a new battery the problem vanished immediately. Before spending tons to replace the steering column give a new battery a try. I am writing from the U.K. where there are a fair number of pre-Western release imported Japanese Prius which is what I own.

Happy Christmas

Hi,

You might check the VIN number of the model:

• NHW10 - the first Prius produced, all text is in Japanese
• NHW11 - the next Prius produced
• NHW20 - the follow-up Prius
• ZVW30 - the current Prius

You've suggested an interesting hypothesis: marginal 12 VDC bus leading to steering stability. I don't think anyone has tested that hypothesis. But then comes the question of why?

If the power steering motors are 'draggy', causing excessive current draw, the 12 VDC bus might see some noise. A regular 12 VDC battery with starter capacity might hold the 12 VDC bus stable.

Bob Wilson

Audio competition grade capacitors might also improve 12 volt stability, and weigh less than a big chunk of lead. Similar price though I suppose.

PSC are you aware of the yahoo group dedicated to the first domestic Prius model? Mk1_prius it is called I think. Most of the knowledge about that model resides there.

I had the same problem from day one on my 2001. The dealer gave me new tires which helped for a very short time. Eventually they replaced the rack and pinion under warranty, but it took a lot of asking about what they called "that little tire shimmy".

Re #16, very disappointing that any Toyota (Prius) official shops can still be uninformed or disingenuous about this situation. It is quite well understood and has been so for many years. The torque sensor contains potentiometers that begin to generate signals that the steerring ECU cannot interpret. The only certain repair is replacement, and due to the design, the entire assembly must be replaced.

It is one of the areas where Toyota's reputation for building high-quality vehicles, and repairing them in case of problems, is being damaged by the Toyota shops. Toyota's only representatives at the maket level. Were I in charge of the parent company, I'd work a bit harder at educating their retail outlets.

Anyway FHariton, glad that you got the new steering assembly. You are by no means the only owner who has had to take the long path to that outcome.

I have a 2003 Prius (now 108 k miles) that started to exhibit the violent steering shudder on the first sharp right turn when first started in the morning. The problem is more pronounced in the cold weather but does not happen every day. It started when the car had 95 k miles on it. The dealer wants $2000 to fix it. No warning lights though. As I notice more 2003 versions reporting this problem, is there a thread or a site where a common strategy is being developed to approach Toyota?

Hi Pani, new poster with the shakes.

Your best bet is to call Toyota at 800-331-4331. Describe your situation, and that you are aware of the history of this problem with NHW11 Prius. There was a warranty enhancement issued but it did not cover the 2003 model year. I imagine that they thought they had the problem resolved, but that does not appear to be so.

if you cannot obtain the replacement for free or cost share from T, then the salvage dismantlers represent another option. Unfortunately we cannot be sure that any of them using the potentiometer-based torque sensors are immune to eventual failure. It was a design error, pure and simple. Sorry about that. Fixed in 2004 with Hall effect sensors.

my 2003 with 72000 miles does the same chatter when first started. it begins after about 15 seconds (enough time to pull out of the garage. the vibration is there even with the vehicle stopped, and I didn't just try to manually steer it, as the vibration is intense. After turning off the key and re-starting the problem did not re-occur. All three instances of this have been in below freezing weather. It seems to be related to a cold start. Once the engine has been running a short time it disappears. I wonder if that might point to something in the boot up of the ECU's ???