2010 Prius Brake problem not resolved even after dealer correction

The Gen3 brake fix isn't supposed to eliminate the delay between regen and friction braking completely, just make the lag equivalent to that found in the Gen2. It should be less noticeable but not completely gone.

 

You hit those brakes they are going to stop you period. Just give it a try in a safe place. I had to. Was going about 25 and I jamb the brakes. I couldn't believe how fast that car stopped.
The only time you are really going to get the sensation is when you are riding the brakes (without a great deal of pedal pressure). You should always keep a safe distance from the cars in front of you.

 

The delay is about 300 milliseconds or so. If you're unable to stop a car short of hitting another car in the millisecond range, you're going too fast to stop in time. Period.

 

300 milliseconds sounds so small. At 60mph you will travel 25 feet in 300 milliseconds. That's about 2 car lengths. Not an insignificant amount at all.

 

Who is experiencing this at 60 mph? And at braking levels where 2 car lengths matters?

I'm still not convinced that even the original braking issue covered these conditions.

 

I've felt it in my 2010. a little odd, but i was expecting it because i read about it. When we're encouraged to brake early and light (using the little charge meter as a guide) it is not a problem, if braking force goes, brake harder. as everyone has said, if you stomp the brakes it will stop, so emergencies are covered. only people riding far too close to a car in front while braking will ever have an accident.

 

If a two car length matters when braking from 60 mph, then it's an emergency braking, in which case you'll slam on the brakes and immediately engage the ABS, which is tied to friction braking. People like to throw around "At 60 mph, the car will travel x feet or x car lengths," but it's not a realistic application in an emergency situation.

 

Like before, we need to know:

• Can you reproduce it at will?
• How frequently does it happen?
• Where does it happen? (need Google map/street/earth address)
• What speed(s)?
• Any weather conditions?

We're not going to have much luck until we can show exactly how to make it happen. Then it becomes trivial to report and often, find a fix.

Bob Wilson

 

To some degree, this situation is apparent in all vehicles with sophisticated ABS and Traction control programs...... I have felt it in my in current 2010 Prius and did feel it in my 2006. I have also noticed a similar kind of sensation in my B-Benz SUV. In the millisecond that a wheel loses contact with pavement on a very bumpy road or pothole situation AND your brakes are applied ... the wheel starts to lock up .... the computer says "NO" and pulses the brake system to control the perceived "skid"..... resulting in a very momentary sensation that the brakes are not working. Keep your foot on the brake and all will be well!

 

Is this a serious post? Everybody knows that the ~300 ms delay between regen and friction is there and reproducible, including in the Gen 2. The "fix" already exists and shortened the delay from ~600 ms to ~300 ms in the Gen 3.

 

I'm glad to say to that I haven't experienced any braking problems with my 2010. I just got it on 4/12/2010, build date of 3/2010. Unfortunately, I've had about 2-3 instances on the freeway where I've had to slam the brakes unexpectedly due to the car in front braking abruptly and the car stopped, without any hiccup.

 

Source?

After SSC-A0B, we no longer see the brake pause that used to happen: under 19 mph; constant brake pedal position; wet or slippery road surface, and; speed bump or equivalent pot hole. There may be other conditions but we need a description of how to recreate the problem.

I measured my Prius braking after the SSC-A0B:

I have yet to find "300 milliseconds" of delay in the braking force. So the questions remain:

• Can you reproduce it at will?
• If so, how?
• How frequently does it happen?
• Where does it happen? (need Google map/street/earth address)
• What speed(s)?
• Any weather conditions?

If you have an iPhone or iPod, you can get one of the accelerometer packages and document the "300 milliseconds." Post the data so we can see what it looks like. Alternatively, I can loan an accelerometer, after instrument rental, that can also accurately measure braking force:


Thanks,
Bob Wilson

 

I thought regen braking is only effective down to 20 mph, and you tested at 19 mph? You ran the same test in NHW11 and still see a delay, or are you suggesting the regen to friction delay is entirely gone in ZVW30? If regen braking and the corresponding delay was indeed effective at 19 mph before SSC-A0B, how do you know SSC-A0B did not raise the speed at which regen braking is effective such that you no longer see the delay at 19 mph?

 

7 mph.

 

Now, 7 mph sounds familiar. I'm curious to see if Bob is actually suggesting the delay is gone in ZVW30 post-SSC-A0B compared to NHW11.

 

The delay is limited to regenerative braking, which is limited to rather light braking. If you really need the brakes, step on them and you get full friction braking right now. There is no delay for heavy braking.

Tom