[Logan01]

The other night a deer stepped onto the road, I hit the brakes. The Prius slowed down, then the brakes released, car coasted a few feet, then the brakes applied again. (deer got away) I tried it again the next day, panic stop from about 50 mph. The car did the same thing. Is this the Toyota version of ABS or do I need to have a talk with the dealer?

 

[hyperion]

Phone call is cheap!

 

[KTPhil]

Sounds more like VSC. ABS usually works at about 10 cycles/second, so it would be a pulsation, not a pause. VSC should also be fast but might take longer the 1/10th sec. Or it's malfunctioning. In any case, call.

 

[Logan01]

Thanks for the replies, I'll be in town tomorrow, I'll stop by & have a chat with the service tech at the dealership. - - it is a bit unnerving when suddenly the brakes release while you're standing on the pedal.

 

[hyperion]

Actually that's what is suppose to happen with anti lok brakes but the cycle should be so fast that you shouldn't notice it.

 

[mdacmeis]

The other night a deer stepped onto the road, I hit the brakes. The Prius slowed down, then the brakes released, car coasted a few feet, then the brakes applied again. (deer got away) I tried it again the next day, panic stop from about 50 mph. The car did the same thing. Is this the Toyota version of ABS or do I need to have a talk with the dealer?

In support of what others have offered, this is a problem, not normal operation. The vehicle speed calculation is being corrupted. Possibilities include damaged front sensor rings, excessive front sensor air gap, or rear integral bearing sensor problems. Then there is the wiring, although that should be caught by the diagnostics. Time to visit the dealer before you "coast" into something.

 

[melgish]

The vehicle speed calculation is being corrupted.

Hmm... isn't there a mod that disables speed reporting to the nav system? Do you have that mod?

 

[Jonnycat26]

The other night a deer stepped onto the road, I hit the brakes. The Prius slowed down, then the brakes released, car coasted a few feet, then the brakes applied again. (deer got away) I tried it again the next day, panic stop from about 50 mph. The car did the same thing. Is this the Toyota version of ABS or do I need to have a talk with the dealer?

There was a long thread about this over on PriusChat, and there are a lot of people who have the same problem.

I can reproduce the problem at will on a certain stretch of road around the corner from my house, and it's not even a panic stop! The lowdown seems to be: The more irregular the pavement, the more likely you are to have the brakes go into "coast" mode.

And just for the "it's not the car's fault, it's yours" folks, I have no mods, and the Trac/VSC lights are not coming on during this.