PS Warning light

Mike,

The Prius power steering system does not include a hydraulic pump and power steering fluid; hence you don't have to worry about low fluid or flushing the system.

You do have to worry about installing a new electric steering gear which will probably cost around $2K or so, not to mention the delay associated with the dealer having to order the part from the Toyota regional parts distribution center.

If your wife doesn't notice serious steering issues maybe she should continue on her journey. However if she notices significant steering wheel twitching, then it is time to replace the steering gear.

 

The problem is almost certanly unrelated to overheating. There are torque sensrs buried deep inside that usually (always?) cause this failure. What year is the gen 1 Prius, odometer, and has it ever had work done on the steering?

It may help temporarily to exercise the torque sensors. I would do this by obtaining 2 pieces of cardboard larger than the tire footprints. Place them in front of each front tire. Drive up on them and stop. Next, turn the steering wheel aggresively in both directions (with the car in 'ready'). Done.

If this seems to delay steering system dropouts, it can be repeated. But eventually a steering rack replacement is quite likely to be required.

 

Hi Mike,

The root issue is that at least one of the two variable resistors buried within the electric steering gear, used as torque sensors, has become "noisy". When the resistors report differing values, the steering ECU concludes that an error exists and illuminates the warning icon on the MFD. Then, when the surface corrosion on the variable resistor went away (temporarily, due to repeatedly moving the variable resistor wiper over the noisy spot), the error is "fixed". Note that the problem happened when Phyllis was in a parking lot, while she is turning the steering wheel to a greater extent than during normal driving on the road.

As the problem worsens, you will find that the steering wheel will start to shake or twitch, on its own. Eventually it will get to the point where the car is unsafe to drive. However it sounds like the car is not at that point yet, so I think it is OK to continue driving it for now (with two hands on the wheel at all times!).

The steering gear on my 2001 had been replaced after the car was a couple of years old due to this issue - which is a well-known failure point of Classic Prius (along with the transaxle and traction battery.)

 

I bought a new 2010 Prius IV one week ago and have driven it less than 200 miles. Last night, I experienced a few seconds of steering wheel shaking while driving at highways speeds. I assumed I had hit uneven pavement. At no point was it difficult to turn the wheel. But after the shaking, the car seemed to sometimes drift to one or the other edge of the lane. I chalked that up to unfamiliarity with the car and to rain and darkness.

After another 45 minutes of driving, and a half hour parked, I headed home on a slower road. That is when my wife noticed that the Electric Power Steering warning light was on. We are both pretty sure it wasn't on before that. This morning, I pulled out of the garage and back in, and turned the wheel both ways as it moved. The light did not come on.

I called the dealer to discuss it. I made a service appointment for Monday so they can check it out.

If you have had a similar experience in a new Prius, I hope you'll post the outcome.

 

Since this is a 2G forum, you probably won't get much response from 3G owners. However I suggest that if the warning light reappears, that you immediately take a good photo of it to show your service writer, thus providing tangible evidence of the problem.

Otherwise, if the light and/or the problem do not appear while the car is at the dealer, the tech will likely indicate "no trouble found" and you'll be billed for one labor hour without effecting any improvement in your car's behavior.

 

That was my first post to this board. I didn't notice the "Gen II" bread crumb.

The photo is good advice. Thanks.

 

Everybody,
I am new to this forum, but I have a 2005 Prius with just over 100k miles on it and the PS light came on this morning. This is the 2nd time this has happened -- the first time was about a month ago and I had it towed into the dealership because I was afraid to drive it. I think they did something with a sensor in the hopes that that would fix it, but, as mentioned above, it came on again today. I drove it around the block a couple of times, parked it in my driveway and went in the house. Came back out a few minutes later and tried it again and it was fine -- drove it over 70 miles roundtrip to work and back.
From the posts on this forum, it sounds like this might be the beginning of an expensive problem -- the steering gear? How soon should I worry about this?
Casmorris
p.s. you should also know that both times have involved record cold temperatures in Arizona (maybe it's temperature-related?), but this car has also been driven in the winter in Maine a few years ago with no problems.

 

2G electric steering problems are rare. If the problem disappears when you power off and then power back on the car, then the problem would appear to be electrical in nature.

I would say that you can drive the car as-is until it gets to the point where the steering gear starts to shake or if the steering does not behave predictably. Then you need to get serious about getting it fixed, but by then the problem should be at the point where the dealer tech can more easily figure out what is wrong - whether the problem is in the steering ECU, the electric steering motor, or the torque sensor located in the steering column.

Note that Classic had an integrated steering gear where the electric motor and torque sensors were included. The 2G components are separate so hopefully that makes repair parts less expensive.