2003 power steering is on /off at hyway speeds

To read for codes, you used what?

-Chap

 

Just in case: 2003 toyota prius power steering rack | eBay

SCH-I605 ?

 

Good, just checking. From screenshots I've seen of techstream, you can monitor the EMPS ECU parameters including the torque sensor signals, and probably also the outputs. Maybe you will get some useful information on that screen while you apply different amounts of torque to the wheel left and right.

-Chap

 

You probably need to replace the steering rack.

 

Likely not the rack, just needs the TSB/recall service done on the PS pinion shaft nut. I havent bothered yet, and have had to "strong-arm" mine part way to work when the PS finally "fails" a 3rd time. Restarting the car usually clears up the steering for a while.

 

Gen 1 Prius has had two different known steering issues that are absolutely distinct from each other. The pinion nut recall is about a purely, absolutely mechanical issue. If you have it, your steering wheel will be really hard to turn to the left; it will not matter what you do with restarting the car, it doesn't count failures, there is nothing electrical about it.

The other issue Gen 1 has had is electrical noise from the sensor that measures your steering effort. That gets fed to the power steering computer, which decides how much voltage to send to the assist motor. That can cause odd steering feel, rapid shaking of the wheel, etc. You can test for that by watching the power steering sensor and output values in techstream. For the mechanical nut problem, there's nothing to see in techstream; it's just a mechanical nut problem.

The pinion nut recall is a bigger operation than replacing the rack. It includes all the steps of removing the rack to the workbench and reinstalling it anyway, plus then partly dismantling the rack to replace nuts never meant to be installed more than once, and it is very unforgiving of the tech doing the work. The good news is, if the tech messes up and notices, they are required to replace the whole rack, and another PriusChat member did recently go in for a pinion nut recall and come home with a brand new rack (after an extra wait for shipment) because of that. The bad news is, if they mess up and don't notice, you can go home with a rack that quickly redevelops the same problem, and they won't do it over (another PriusChat member recently experienced that).

There are lots and lots of threads in this forum about the electrical sensor issue. The official fix for that is just to put in a new rack, if that's what's happening. There aren't as many threads on here about the pinion nut issue, but if you are curious what it is and why it makes the wheel hard to turn left, you can read about it here.

-Chap

 

Thanks! I was unaware that there was more than one issue. Mine has the 2nd one, but ive received service cards for the 1st one.

 

Is the dealer the only way to find out if campaign was done on my MILs car

She has no idea

 

I think for some recalls, they're supposed to add a sticker somewhere ... door jamb, maybe? But I'm not sure about that one.

Otherwise, yeah, the dealer, or the toyotaowners web site.

-Chap

 

Perfect, Thank Sir Chapman.