2006 Prius shudder when braking

Welcome to the forum!... I have never thought about the position of the engine as it stops.. but that makes sense.....

Mine doesn't diesel either, but I have heard reports and many veterans say it does happen..... maybe its intermittent or we are just forturnate.

 

Thanks for the welcome.

Just to clarify, I don't dispute that something is occurring, just that the likely cause is not dieseling. Not in a traditional sense/manner of a carburetted vehicle anyways.

 

I too experience the grab-release-grab-release braking on our week old Prius and at each grab (or is it at the release) I hear a low volume pop. I wonder if pedestrians can hear it or just me inside the ultra quite car? I hear it more than I feel it. Just as others have noted it begins at 3 MPH until completely stopped. If I press firmly on the brake during a quick stop it does not do it, only when I’m lightly touching the brake. Also, it does not do it when the car is cold making the first run of the day. I think it is the brake pads sticking to the surface of the disk brake, but that’s simply a guess. Worth noting the ICE is off long before the 3MPH point, in fact just as Bob R. notes (post #8) I can hear the “whine†noise as I’m slowing. Luck of the draw I guess, but my ICE shuts off with an obvious sputter too. Sometimes it is perfect, hardly noticeable so I know how well it can be. Perhaps these issues will go away after the car is broke in good, but will mention these and future things that will pop up when I take it in for its first oil change.
Both my wife and I absolutely love the car, but I am one of those sensitive drivers who feels and hears everything, which after a few weeks (months) will subside when I realize its just a car. I’ll start eating in it and squeeze in between two 4X4 trucks instead of parking in the far corner of the lot so I don’t get that first door ding.
My commute is 24 miles roundtrip in all kinds of traffic situations with a few small hills and have averaged 45.8 mph, indicated (Consumption Display), in the first half tank of gas. When I run a short trip, 2 to 3 miles, it dips down less, but makes up for it when I do another commute to work. It’s been cold here since we took delivery with 30 degrees F typical during commute times. We are about 5,400 feet elevation.
Since this is my first post I’ll give a few more details. We put a $1,000 refundable deposit on November 5th and received the car January 20th. Paid MSRP. Decided to get off the fence when both Colorado and the Federal governments were offering hefty tax credits, which there is no guarantee I’ll get. I thew the dice so will see what 2007 tax time brings.
In spite of my picky comments about the noise etc. we are both so excited and happy with our first Toyota it’s like being a kids again. Thanks to all the PriusChat posters, your info helped make some tough decisions regarding the choice of car.

 

Funny (or not so funny because this is really starting to bother me), but I have an 2005 that also does this brake shudder when close to stopping. And from what I can tell, this is not the result of the ICE shutting off.

I distinctly remember not feeling this when my '05 was new, but I don't know when it started. I want to say it started after I got my car back from the ECU update in December 2005, but I honestly can't say I know for sure.

What I do know is that as I grew more aclamated to the Prius, I have been instinctively compensating for its unique driving feel, i.e., my acceleration behavior, braking behavior, EV cruising, etc.. It was a conscious snap into reality that made me realize there was something not right about how the car stops, i.e., the shuddering.

I currently have 19K miles on it and it's 16 months old.

I will make an issue of this because I don't believe this is an intentional behavior for this generation car. Plus, if I experienced this when my car was new, I would have noticed it right away since "normal" cars don't do this, unless you have alignment problems, tire grip problems, warped disks or damaged brake pads, etc. all of which I will check for.

This is especially unacceptable from any brand new car, hybrid or not.

 

I'm getting the same release-grab action in my new 06.

I can easily invoke it by slowly releasing braking pedal pressure under 3mph. Most of the time it occurs synchronously at both front wheels, but sometimes the right wheel releases slightly after the left. Not a big deal, but I like to make smooth stops by easing off the pedal just before coming to a complete stop.

This is definitely a control system/software issue. Being brake related, I expect we'll see a recall sometime soon.

BTW, are any 06 owners noticing other new behaviors? My ICE routinely shuts-off at 50+ MPH on down hill grades. It was even running battery only downhill at 70mph!

 

I don't think that is new for the 06 the 05 I test drove did the same thing (ain't it cool though?). It's actually not shutting off the ICE as I believe it's still turning but using very little (or no?) gas. It does save a lot of gasoline though!

 

Grabby brakes are a known problem. If searching deigns to stop
giving SQL errors one of the days, search for "grabby" or "grabbing"
in topics, and/or see near the end of
http://techno-fandom.org/~hobbit/cars/prius-log/003.html
for my own experience with this and the solution.
.
This oughta be in a FAQ someplace...
.
_H*

 

My Prius is 1 month old today! I've been lurking around the site for a few months now, but I figured it was finally time to join. So I have a bit more than 1000 miles on my car, and I've noticed a shudder as well. However, mine occurs just after I've come to a complete stop, usually after stop and go driving in traffic. It doesn't happen every time, but within 5 seconds of stopping, my car will shudder pretty violently. So from what I understand, this is normal? Or should I get it checked out? Irregardless, I love my Prius!

 

I have a long commute (45 miles one way) to work with very few stops. I seem to be getting the shudder mostly on days when I'm off and running errands, with more stop and go traffic. Sounds like this is normal. Glad I found this forum, otherwise I'd be making my dealer crazy with questions

 

<div class='quotetop'>QUOTE(brasche @ Feb 10 2006, 01:31 PM) [snapback]207244[/snapback]</div>

Above 41 mph the ICE must spin to avoid over reving MG2. It may not be getting any fuel, but it will be spinning under the control of MG1. The energy display is an approximation of energy flow, but does not necessarily show when the engine is not spinning.

 

Yes, I feel a bit of grabbiness (is that a word?) in the low-speed braking. I've got about 1700mi on the car.

 

<div class='quotetop'>QUOTE(OaklandPrius @ May 17 2006, 09:15 PM) [snapback]257258[/snapback]</div>

That would be the ICE shutting down, the shudder is much more pronounced when the engine is cold and 'asking' "hmmm, should I shut down or not". When it is warm (engine AND air), it is almost unnoticable. If I recall, it was more pronounced when my car was new except when the air temp is cold (like 15 F or below).

There is no 'engine is running' indicator in the car. For those who have posted 'the engine is definately off because I'm in electric': Not necessarily, unless you have the EV mod that forces it into electric. That WILL shut down the ICE. Otherwise there is a temperature/power requested/time based process the computer uses to decide to shut down the ICE. It might shut down as you slow, as you stop or after you stop.

As for the potential shudder being related to the brakes in the 2006, we are picking up my wife's Barcelona tomorrow, I'll be on the lookout for this as it definately has never been a problem with my '04. I'll be happy to be a passenger in the '06. I have been in her current vehicle exactly twice since buying my Prius. Once when I had surgery and she drove me to and from the appointment. I 'made' her chauffer me in my Prius for 2 weeks after that until I could drive again. I think that is when she decided her next vehicle would be a Prius. The other time was when we went to jump a friend's car with a dead battery. Can't do that in your Prius, unless your friend ALSO has a Prius. (which is now the case with THAT friend )

 

I haven't read every post in this thread, so pardon me if this has been covered already.

The shudder discussed can be from either of two causes. The braking switching from regen to hydraulics at around 6 to 8mph has been covered many times.

The engine shudder is a function of design. When the engine shuts down it must be prepositioned for a reliably quick restart. Therefore, if the cranksafht comes to stop a few degrees (of rotation angle) from the required position, it is forcefully rotated to the proper position. So, if the engine has almost completely stopped rotating, then needs to be driven to its proper angle it will either 1) rotate only slightly and not be noticed by the driver, 2) rotate moderately and be noticed if one is paying attention, or 3) rotate thru close to the max possible angle and be felt as a shudder during and/or as the stop position is reached.

I read this at a site which I can no longer find. It may have come from the book about the the design of the Ist Gen Prius (which I have saved on my PC). My 2005 Prius and my 2006 Prius have both done this and I consider it perfectly normal.