Car lurches when brake applied and hitting a bump

Normally you are using regen when slowing down. If you hit a bump, the car systems will switch from regen to normal abs friction braking.

The lurch you feel is that moment of changeover.... it feels a little like you lost braking and sped up, check that the recall was done for this which basically shortened the slight delay to an even shorter event.

Roland

 

There are several threads about this here on PriusChat.

"Lurching" forward on braking over bump problem anyone? | PriusChat

Prius sometimes lurches forward when I apply the brakes. | PriusChat

Data on "brake loss" (aka "sudden acceleration&quot after bump | PriusChat

Lurching while braking | PriusChat

SCH-I535

 

Ok a617, going to the dealer now is the right course of action to take.

I cannot think of anything aside from the changeover issue at this point that would explain what you've described. Hopefully you'll be kind and inform us of the outcome to help the community understand the issue you have experienced.

Roland

 

All vehicles I have driven with ABS do this to some extent. Some worse than others.

 

Momentary ABS activation maybe ?
That can be rather alarming if you are not familiar with the feel of ABS, and sometimes even when you are familiar with it.

 

Yep had that happen when the car was a few days old. Had to do a "panic" stop, traffic slowed quicker than i anticipated in front of me. Hit an expansion joint before a bridge and it felt like i wasn't going to stop. The ABS had kicked in for a fraction of a second. Felt the pulse. Then car stopped real quick.

The moment it switched over, on the bump it felt like it kept going. My real issue is personal though, I was coming from a Toyota Tundra which is much heavier and brakes much differently. But even then I've felt that uneasy feeling like the pedal had gone down further, so i pressed harder.

 

The braking transition from regen to friction brakes can be unsettling the first time it happens to you. To get a feel of what the transition feels like in controlled conditions, when braking for a stop light without traffic in front of you, shift to Neutral. Neutral will disable the regen and enable friction braking, the same as when you hit a pothole or slick surface and kick in ABS. There will be a difference in brake pressure needed for the same decel rate between the regen and friction braking.

 

This dead horse has been kicked over and over again with the gen 3s on Priuschat

 

Maybe yes, maybe no bs from the dealer....

Mine is an early 2010 and did get the firmware update for the delay.... it is still there though, but a fraction or two of a second shorter.

Think about your car stopping as a 3 step process, 1 regen brakes, just the two front wheels being used by the motor generator to charge the battery up, 2 friction brakes if you press fairly hard or are nearly stopped, and 3 activation of the abs system.

This selection between the 3 seems to take just long enough on a Prius to notice it, but the car can easily stop just in just as short a distance as any other car on the same surface given equivalent grip at the tires. I've found it even better than some I've owned when once my PCS system thought I might hit a guy who cut me off... it jacked up the brake response and it felt like an anchor with a short chain was dropped.

You'll grow used to it in time, and if you still wonder... rent a Prius or take a test drive in a new one to check it out on a similar set of road.

I avoid having to brake hard on rough sections when I see myself coming up on such a stretch of road... of course you cannot do that sometimes.

Roland

 

i think you need to go back and apply the thumbscrews to that dealer.

 

I think you should try to get used to it.
Try to adjust your driving style. Be aware of how the car reacts when ABS kicks in and forget about wating your time with the trips to the dealer. Then move on....

 

I had a 2011 Prius that did it. When I bought the car new the salesman told me about this characteristic in a Prius. You are right, get used to it and move on. I have a 2014 Avalon Hybrid XLE Touring and it does not do that but the Prius does. Nothing can be done about it. I put 48,000 miles on the Prius and never had an accident because of it but I certainly think you could.

 

Here's the deal:
A LOT of owners on here told you that it probably is normal (can't say for sure without driving it).
Then a dealer told you it is normal.
Seems to me like you have a few choices going forward.
Sell the car if you don't like it.
Find another dealer for another opinion.
Resign yourself that it doesn't work like you WANT it to work and adjust your expectations.

Continuing to fret about something you can't really change is not healthy.