[The Traveller]

DrCez, on Feb 4 2010, 03:56 PM, said:

flow, on Feb 4 2010, 02:31 PM, said:

Toyota must clearly know there is a problem...Its now been reported on here & Priuschat, not to mention all the people that contacted their local dealer about it.

Im assuming, because the car doesnt physically accelerate (just gives that sensation) they are saying its not dangerous?

Quoting this article on the BBC website:

"As depressing the brakes further activated normal braking, Toyota said the glitch was not legally a safety hazard and said it had received no reports of any accidents related to it."

This is exactly my experience on the two occasions I have experienced an unexpected reduction in braking with my Gen 3: the first time it was scary but I instinctively pressed the pedal harder and the car began slowing again. The second time (a few months later) I ran over a damaged drain cover while braking but I suppose I was more prepared to push the brake pedal harder and it wasn't particularly frightening. Some are suggesting that the problem is more apparent in certain cars; in my case it's infrequent enough not to worry me but were anyone else to want to drive my car I would warn them to watch out for this unusual behaviour.

I suppose part of the problem is that other cars don't behave like this: for a given amount of brake pedal depression you get more-or-less even braking force, and in this respect the Prius could catch you out. If it can be remedied with a software fix then all the better.

Thanks to all for keeping track of the issue, it's really valuable information, so keep on posting

A brief report on the BBC News channel late this afternoon suggested that Toyota have admitted a software problem between regen braking and ABS. They are now working on a fix.

[dmeredith]

My wife and I both have the problem regularly on our 4 month old Prius when going over speed humps - the brakes release for about 1 second as the front wheels leave the hump and go back onto the road. The main problem we have is that there is a speed hump near us that is just before a turning on the right, so if someone is turning right (and they often don't bother to indicate until they start to brake for it) you have to brake as you go over the hump and the momentary loss of braking causes you to get much closer to the car than you'd like!
It seems to be related to regenerative braking as it doesn't seem to happen when braking over humps if you put the car into neutral first (in drive I can repeat it nearly every time). Having monitored road speed while repeating the effect it's clear that the car doesn't accelerate, but for about 1 second (just under) the car stops decelerating and maintains its speed.
Hadn't mentioned it to Toyota as we were waiting for the 10K service to come up, as no-one else seemed to have had a fix for it anyway.

[Scottle]

I've had this happen four times in the month that I have owned my Gen 3.

As for the feeling of acceleration when this happens could this be due to the car having an auto (CVT) gearbox and as such when not braking the car will accelerate, just as when you release all the parking brake with the car in drive??

[Fujisan]

I am sorry, I my opinion, this is no more than just a characteristic of the car.

If you owned a powerful rear wheel drive car, even before you sat in it you could expect that if you entered a bend too fast, the back end to come out and depending on your skill level, you might head backwards into a hedge. That is the charactistic of that car and with correct reading of the road you would avoid the situation.

This is slightly different in that this characteristic is only revelled either by research on forums like this or PriusChat or by first hand experience.

Having experienced this characteristic myself once and I'll agree that it isn't a nice feeling, but we then should be able to recognise the road conditions that might provoke this characteristic and alter our driving accordingly where possible (brake earlier on a smooth surface, give extra distance between cars, etc) and in unavoidable situations expect and not be shocked by this characteristic.

Some people have mentioned that they felt this characteristic over several seconds. I wasn't in the car with them so I will not disagree with their assessment. But in my opinion, milli-seconds would be a more accurate figure, even if it felt longer.
I will ask you to do a few small experiments:
Just count to yourself while you press the brake pedal in any given situation and you will be amazed just how short a time you are actually on the brakes and how quickly speed is scrubbed off.
Next, travelling at a steady speed, when you pass a landmark (road sign, whatever), count to yourself, two or three seconds and then look back in our mirror and see just how far you have travelled in those two or three seconds.

If Toyota do have a software fix for this characteristic all well and good but in the mean time I will rely on reading the road correctly, using correct observation (I am sure any former bikers know the importance of watching out for diesel spill's on the road surface) to be cautious when braking on broken road surfaces.

[Grumpy Cabbie]

Fujisan, on Feb 5 2010, 12:07 PM, said:

I am sorry, I my opinion, this is no more than just a characteristic of the car.

If you owned a powerful rear wheel drive car, even before you sat in it you could expect that if you entered a bend too fast, the back end to come out and depending on your skill level, you might head backwards into a hedge. That is the charactistic of that car and with correct reading of the road you would avoid the situation.

This is slightly different in that this characteristic is only revelled either by research on forums like this or PriusChat or by first hand experience.

Having experienced this characteristic myself once and I'll agree that it isn't a nice feeling, but we then should be able to recognise the road conditions that might provoke this characteristic and alter our driving accordingly where possible (brake earlier on a smooth surface, give extra distance between cars, etc) and in unavoidable situations expect and not be shocked by this characteristic.

Some people have mentioned that they felt this characteristic over several seconds. I wasn't in the car with them so I will not disagree with their assessment. But in my opinion, milli-seconds would be a more accurate figure, even if it felt longer.
I will ask you to do a few small experiments:
Just count to yourself while you press the brake pedal in any given situation and you will be amazed just how short a time you are actually on the brakes and how quickly speed is scrubbed off.
Next, travelling at a steady speed, when you pass a landmark (road sign, whatever), count to yourself, two or three seconds and then look back in our mirror and see just how far you have travelled in those two or three seconds.

If Toyota do have a software fix for this characteristic all well and good but in the mean time I will rely on reading the road correctly, using correct observation (I am sure any former bikers know the importance of watching out for diesel spill's on the road surface) to be cautious when braking on broken road surfaces.

It has happened to me a number of times and can be milliseconds or on one occasion about a second or so! It depends on the road surface I believe as well as your reaction time!

[Trafficman]

Grumpy Cabbie, on Feb 5 2010, 12:15 PM, said:

Fujisan, on Feb 5 2010, 12:07 PM, said:

I am sorry, I my opinion, this is no more than just a characteristic of the car.

If you owned a powerful rear wheel drive car, even before you sat in it you could expect that if you entered a bend too fast, the back end to come out and depending on your skill level, you might head backwards into a hedge. That is the charactistic of that car and with correct reading of the road you would avoid the situation.

This is slightly different in that this characteristic is only revelled either by research on forums like this or PriusChat or by first hand experience.

Having experienced this characteristic myself once and I'll agree that it isn't a nice feeling, but we then should be able to recognise the road conditions that might provoke this characteristic and alter our driving accordingly where possible (brake earlier on a smooth surface, give extra distance between cars, etc) and in unavoidable situations expect and not be shocked by this characteristic.

Some people have mentioned that they felt this characteristic over several seconds. I wasn't in the car with them so I will not disagree with their assessment. But in my opinion, milli-seconds would be a more accurate figure, even if it felt longer.
I will ask you to do a few small experiments:
Just count to yourself while you press the brake pedal in any given situation and you will be amazed just how short a time you are actually on the brakes and how quickly speed is scrubbed off.
Next, travelling at a steady speed, when you pass a landmark (road sign, whatever), count to yourself, two or three seconds and then look back in our mirror and see just how far you have travelled in those two or three seconds.

If Toyota do have a software fix for this characteristic all well and good but in the mean time I will rely on reading the road correctly, using correct observation (I am sure any former bikers know the importance of watching out for diesel spill's on the road surface) to be cautious when braking on broken road surfaces.

It has happened to me a number of times and can be milliseconds or on one occasion about a second or so! It depends on the road surface I believe as well as your reaction time!

[simon stanleigh]

HI there,
would you be able to give me a call at Channel 4 news about your Prius? thanks Simon Stanleigh 0207 4304626

[Trafficman]

To add my two pennys' worth. I did 75,000miles in a 55 Mk 2 and had this maybe 4 times and put it down to Nanny Prius trying to take too much care of me. Not pleasant, but never dangerous. I have as yet not had it with my Mk 3 in 7,000 miles.

Yes it would be good to have it sorted, but come on folks, the washing machine scares me more!

[Fujisan]

simon stanleigh, on Feb 5 2010, 12:21 PM, said:

HI there,
would you be able to give me a call at Channel 4 news about your Prius? thanks Simon Stanleigh 0207 4304626

No thank you.

Trafficman, on Feb 5 2010, 12:24 PM, said:

Yes it would be good to have it sorted, but come on folks, the washing machine scares me more!

Nice one Trafficman

[flow]

Fujisan, on Feb 5 2010, 12:07 PM, said:

I am sorry, I my opinion, this is no more than just a characteristic of the car.

Sorry but i totally dissagree with that. There is a design fault/software glitch, caused by the regenerative braking (?). Whether its classed as dangerous is open for discussion - when it occurs, the car doesnt actually accelerate, it just gives that impression (abit like a virtual reality ride).

Its happened to me dozens of times, mainly if there is a pot hole by a junction & as a result im more aware of it. Its got nothing to do with how careful you drive the car. If anything, stamping on the brakes will stop it from happening as normal braking wil occur.

The main thing is, Toyota have now accepted there is an issue & have developed a software fix for it. The issue now is getting them to order a recall here as well as in the usa/Japan.

[Fujisan]

flow, on Feb 5 2010, 12:53 PM, said:

Its happened to me dozens of times, mainly if there is a pot hole by a junction & as a result im more aware of it. Its got nothing to do with how careful you drive the car.

Exactly
You are now careful where you drive and try to avoid the potholes. A good technique to be practised in all cars if possible for the continued health and wellbeing of your car.

[flow]

Fujisan, on Feb 5 2010, 01:08 PM, said:

flow, on Feb 5 2010, 12:53 PM, said:

Its happened to me dozens of times, mainly if there is a pot hole by a junction & as a result im more aware of it. Its got nothing to do with how careful you drive the car.

Exactly
You are now careful where you drive and try to avoid the potholes. A good technique to be practised in all cars if possible for the continued health and wellbeing of your car.

Not all cars have a braking issue like the prius - When i drive another car, I will contunue to be careful of potholes - for fear of damaging the suspension, not giving me a fright over the braking

[johalareewi]

Trafficman, on Feb 5 2010, 12:24 PM, said:

Yes it would be good to have it sorted, but come on folks, the washing machine scares me more!

And so it should...
http://www.dontgivef...afety/1415.html

[Grumpy Cabbie]

simon stanleigh, on Feb 5 2010, 12:21 PM, said:

HI there,
would you be able to give me a call at Channel 4 news about your Prius? thanks Simon Stanleigh 0207 4304626

Maybe someone should ring this guy as it now appears that Toyota UK are saying that the UK RHD version is different to the US & Japanese Prius's and doesn't have this brake issue!!!!

Yeah sure it doesn't.

Brings into question of how someone in the UK reports such issues as we have to trust the dealer and the manufacturer to do something unlike in the USA where they have the NHTSA http://www.nhtsa.gov/ who are an independent body.

Perhaps that's a story the press can look into?

[wooski]

Except the Jap cars are RHD too! I just don't buy our UK cars and Jap cars are any different in this regard.

Madness.