Brakes locking

Reminds me of a phone conversation I had years ago with a tech support guy at USRobotics. I told him a detailed story of what my USR modem was doing, what happened when it was supposed to connect, and when I finally stopped for air he said:

"Sounds broke."

So he sent me one that warn't broke.

 

Locking brakes on an ABS-equipped car are never normal. I'd have in the dealer's shop asap. But if it's intermittent, they might have a hard time diagnosing it.

 

Is the cruise control working?. If not than something could be wrong with abs or sensors on front wheels?

 

I have noticed touchy brakes, on our 3rd gen. Typically at start up, mostly in reverse IIRC. First time I was backing up in a parallel parking space, in prep to exit: touched the brake and thought I musta tapped the guy behind; it was so abrupt and total stop. My hunch is the electronics at play, not mechanical.

 

Since new? That would have made it a warranty failure back then, but unfortunately the basic warranty for that level of non-hybrid components is probably long expired by now.

Just to confirm that the brakes are really locking: you are smoking the tires when this happens on dry pavement? Leaving skid marks? And sliding/skidding and losing steer control on that wet downhill?

I must ask because the Prius ABS feels much different than on my prior car, and is much smoother without the old familiar rapid pulsation. In dry conditions it feels like it is trying to dig up the pavement. And with the electronic Brake Assist (BA) feature, it was surprisingly easy to inadvertently trigger full panic-level ABS braking when I "either jab on them or press hard", until my reflexes were re-trained. But in my cases, it was not actually locking up, the stops were still perfectly straight. And quick.

 

Do you have access to Techstream? What information is saved in the ABS activation history?

 

NO, absolutely NOT normal.
And probably dangerous too.
I can't imagine you NOT taking it to get it fixed after hitting another car with no ABS activation.

BUT.....some tests on a deserted road or empty parking lot might be in order.
Wheels will sometimes skid a little bit even with ABS activation.
But it doesn't sound right to me.

 

kick it on the side, might help! but seriously that sounds dangerous.

 

i have to wonder about driving style, since i have never locked up the brakes in 50 years of driving over 40 or 50 different cars

 

Same (although much less years and cars) .

 

This might be related to something I have noticed, don't know. And I'm only reviving this thread from a little over a year ago. Every once in a while I get a "touchy" brake pedal. The best example of what is happening, that I can think of, is it is like electric trailer brakes. And I usually notice it at low speeds, maybe even less than the 7 mph where regenerate stops and friction brakes take over. But sometimes it is doing it when decelerating from higher speeds, like in the exit lane from the interstate. Every time it happens I try to do some research, but that is often difficult in traffic situations. There is a point though in the brake pedal travel where it distinctly grabs and lets go. Have not been able to observe if the brake lights accompany this on and off cycle, which would be interesting but perhaps unrelated. I think in most situations where this happens I am using DRCC, but that would be put in standby with the first brake press. I asked my Toyota service writer about this over a year ago and he said no one else has reported this as a problem. I have not experienced any loss of control or handling problems. I do mostly dry road driving. Sometimes there could be an inch or more of standing water on the road though, which worries me a little. No ABS or VSC lights, and I'm not sure about any MIL codes which I might have checked at the next tire rotation. My Gen III and II had a nice, smooth braking curve. Should I be concerned?

 

I will also say on my 2016 I cant say definately they are locking, but they are VERY grabby. Its always one of those scenerios where someone comes to an abrupt stop and while I hit the brakes hard out of the gate, I didn't mean for the car to go full panic mode, like I'm a little old lady who cant hit the brakes hard when intending on hitting them hard, but never the less the car grabs the brakes like a collision is imminent. This is the first "new" car I had with ABS but I always thought that the abs never worked quite as good as I thought it should have. I will however say the car stops super quick in like every scenerio so I am sorry to hear about the fender bender and glad everything was ok.