Question on Electric Power Steering, i have no steering assist.

Better see your dealer first.

 

You can find repair manual info at techinfo.toyota.com

 

How did you check for the no DTC condition? If there is a major malfunction, and an indicator on the dash, then some DTC would possibly be set. A generic scanner won't read the Prius specific PS ECU codes.

However, if there really are no DTC, then that means that the 12VDC to the ECU has failed. If the ECU has developed a short, it should blow a fuse, probably the EPS fuse.

The PS ECU is located above the steering column. You have to dismantle the driver side dash to get at it, search for those instructions here. Otherwise, it is a plug-in affair, so not a problem to change.

 

Well done, glad to hear that it turned out to be a simple fix. That code reader you used likely only reads the generic engine related PID's, and won't read any of the other ECU's in the Prius. If you want a Prius code reader, look for "mini VCI" on eBay.

I would expect that if you have no driveability issues, and the steering wheel is centered, then nothing more is required as to calibration. If you end up having the steering column replacement safety recall done, the dealer will do that step anyway, or at least should do so. Congratulate yourself for having saved many $$$ over the dealer's price.

 

I had the same problem with my '06 Prius. No power steering, the red triangle with the exclamation, and P/S on the display. I went into diagnostic mode, took pictures of the codes under the different menu options in case I needed them, and cleared all the codes. Turned it back off, and when I started it, the power steering worked. I only used it for a day since, but so far so good. No parts needed.

 

I would say that it is too soon for certainty. Failure mode for any electronics certainly includes intermittancy, so if the problem returns some day, we will not be surprised. Not a difficult fix, if it is a similar ECU replacement.

Note that those diagnostic mode displays are of no real use in troubleshooting.

 

No they won't; they'll screw up your perfect steering like they did mine and everyone else who has had the recall shaft done. It results in the dreaded 5 degree off center syndrome.

 

It can't be all that bad. Mine came out of the dealer perfectly aligned.

 

I guess I am unlike "everyone else". I had the steering recall done and the steering wheel was dead center when I got it back. When I took it in, it was off about 2 degrees. Now perfectly flat.

 

As an update, it has been five weeks and my power steering has still been working perfectly. All I did was clear the codes through the diagnostic screen.