Will not go over 65 mph

The Prius uses a magnetic encoder in the wheel bearings for VSC, I believe, and if the Hall sensor pickup is poorly positioned, or if the encoder is damaged either mechanically, thermally or magnetically, it is possible that a marginal signal would degrade with speed, or that the resultant error in readings between the two wheels would be proportional to the vehicle speed.

So, as speed increased, error could eventually grow large enough to exceed the VSC set point, and the car would not accelerate beyond that point.

In any case this is a dealership/warranty issue.

 

Nobody said you were. I'm sure you'll agree the Prius is a complicated car. I'm a chemical engineer, no way in hell I'd touch most of the systems

You stated you service your own vehicles. Whatever you do, never EVER attempt to bleed the brakes on a Prius yourself. It cannot be done without the Toyota scantool

http://priuschat.com/forums/attachm...n-bleeding-prius-brake-bleeding-procedure.pdf

Just a heads up for you.

 

Please let us know how the mystery resolves.

 

I second that

 

The only time I had a problem like that was when I got a flat and was driving on the spare tire to get it replaced. I couldn't get above 30 before the traction control kicked in and slowed the car down.

 

Last summer the RF tire on the 2004 blew when my wife hit some road debris. I put on the spare tire and the car worked OK, the speed limit on that road is 65 mph so no problems at that speed. I'm wondering whether Trevor's spare tire was underinflated.

My guess also is that there's either something wrong with one of the tires, either underinflated or the wrong size compared to the other three; or a wheel sensor is producing a marginal signal.

 

well i would say either

1) release the parking brake

or

2) take it out of "B" mode...

but seriously, very interested to find out as well what the resolution is.. and its much easier to track this thread if i post

 

That flat tyre will look ugly by the time he gets home hey?
Just a guess. Has the son looked at the tyres?

 

It does sound like its a problem with a wheel speed sensor. Had that happen on my SL2, but as it did not have VSC (just ABS and TC), the symptom was the brake calipers would thud on and off as one came to a stop.

Saturn Tracked it down to a cracked hub, which apparently messed up the reluctance sensor. They had to call the regional tech, and he knew what it was right off. Reluctance sensor loose sensitivity at slow rates of permeability change. The cracked hub apparently thru it off. Never actually saw the damage. So, am not real clear on why it was not working. It was covered under waranty.

Lots of possibilities as to what could be wrong with the something like the sensor or its wiring. Or even the ECU receiver, but that is unlikely if its a Hall sensor, which will have an integral TTL driver and a large noise margin output signal.

 

You have my permission to smack him

 

must not be his car, or he might actually care about it.

 

You have to stop talking like that, or some of us might think that you are a responsible adult.

Tom

 

This happened to me after I reset my ABS/VSC System with my tech stream. Same tires as I’ve always had since I got it. It’s only as I approach 60mph, the light starts flashing and it acts as though I’m loosing power, like it would when the traction control kicks in when the front wheels start to spin? Weird.

 

techstream displays each of the 4 wheels calculated mph. Use it to observe all 4 mph readings while having someone else drive. You should be able to determine the problem child pretty clearly.

 

Ya know, you don't have to post the exact same problem on four different threads. Either some one will read the first one and respond, or they won't.

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