?? Prius brake problems an issue for Lexus hybrids

sleepysurf · 02-03-10, 07:09 AM

Starting to see reports of Prius braking problems in the press, including reports from Japan...
http://news.yahoo.com/s/ap/20100203/...n_toyota_prius

I'm wondering if there might be a generic problem developing over time with regenerative brakes. Anybody know more?

Cruiter · 02-03-10, 08:21 AM

Quote:

Originally Posted by sleepysurf

Starting to see reports of Prius braking problems in the press, including reports from Japan...
http://news.yahoo.com/s/ap/20100203/...n_toyota_prius

I'm wondering if there might be a generic problem developing over time with regenerative brakes. Anybody know more?

I have an early build RX450h (built in May of '09) and have driven it on dry roads, wet roads, roads with snow, and gravel roads. I've experienced exceptional braking in all conditions. In fact my only uncomfortable moments were very early on when learning how to judge the feel at 'creeping' speed in the garage. That isn't a problem, but more a period of acclimating myself to the feel of the car. Electric brakes 'are' different. They work just as well or even better in some situations. You just need to get used to them.

I'm coming up on my 10,000 mile service and the only thing extra to do at this point is upgrade the NAV system to 9.1 Ver.

We don't need to 'hype' problems by association. If there were an issue we'd have read it here before now from owners with the issue.

'nuff said.

Stormforge · 02-03-10, 03:34 PM

i can say with a 95% confidence level that we don't have this problem.

RXSF · 02-03-10, 03:36 PM

there is another thread about this: just go to the main clublexus page and scroll down to car chat.

wyau01 · 02-03-10, 10:22 PM

I had braking issues with the first Gen on ice, but didn't experience anything with the 2nd gen hybrid. Knock on wood.

sleepysurf · 02-04-10, 12:27 PM

Looks like the brake issue is not the only "software" related problem...
http://news.cnet.com/8301-13924_3-10...?tag=mncol;txt

Fortunately, if these "anomalies" are indeed "software related", they should be able to come up with a fix, presuming, of course, that dealers can "flash" new codes via the system bus.

SLegacy99 · 02-04-10, 06:46 PM

With all of the Toyota "issues" pervasive throughout the news at the moment I chalk this up to nothing more than hysteria.

kitlz · 02-05-10, 02:21 AM

I'm going to the dealer this morning and will ask about the pending recall from Toyota on the Prius and HS250h. I'm not into the hysteria, just curious to see what they know.

kitlz · 02-05-10, 06:57 AM

So I talked to the service manager. He has not heard anything about the brakes on the HS250h. In fact I have one as a loaner. We'll see.

chinpokomo · 02-05-10, 04:20 PM

In the following article, the reviewer described a brake problem in the 450h that is very similar to what the Prius owners and Toyota have confirmed:

Quote:

The RX's brakes, however, are horrendous. Just as in the first hybrid I ever tested, the RX's brakes engage when you push down on the pedal, then release briefly and engage again.

http://www.cars.com/go/crp/research....ection=reviews

Interestingly, the reviewer also mentioned that he did not notice such a problem with the new Prius.

kyo7878 · 02-06-10, 07:21 AM

i've done quite a bit of test driving on 450h (fwd) before putting down my deposit. i tested on speed bumps going downhill & did not notice any signs of brake disengaging or slipping~ no chance of testing on ice though...as i live in tx i'm not too worried about that part~hehe

SLegacy99 · 02-06-10, 08:00 AM

Quote:

Originally Posted by chinpokomo

In the following article, the reviewer described a brake problem in the 450h that is very similar to what the Prius owners and Toyota have confirmed:

http://www.cars.com/go/crp/research....ection=reviews

Interestingly, the reviewer also mentioned that he did not notice such a problem with the new Prius.

I've never had a problem.

1SICKLEX · 02-13-10, 10:16 AM

I've driven EVERY Lexus hybrid and braked hard in the all. I think I've experienced what they are feeling but its not a brake failure, just the "feel" goes flat for a min-second. This is also a normal feeling when you go over a bump.

I find it funny now everyone is paying attention to how they actually drive

. Maybe these same people will stop texting while driving and get out the fast lane going 40 mph!

wyau01 · 02-13-10, 11:56 AM

Quote:

Originally Posted by Cruiter

I have an early build RX450h (built in May of '09) and have driven it on dry roads, wet roads, roads with snow, and gravel roads. I've experienced exceptional braking in all conditions. In fact my only uncomfortable moments were very early on when learning how to judge the feel at 'creeping' speed in the garage. That isn't a problem, but more a period of acclimating myself to the feel of the car. Electric brakes 'are' different. They work just as well or even better in some situations. You just need to get used to them.

I'm coming up on my 10,000 mile service and the only thing extra to do at this point is upgrade the NAV system to 9.1 Ver.

We don't need to 'hype' problems by association. If there were an issue we'd have read it here before now from owners with the issue.

'nuff said.

I heard you will need to update the firmware on the NAV before the 9.1 map data.

YotaCarFan · 02-13-10, 03:28 PM

Quote:

Originally Posted by sleepysurf

Starting to see reports of Prius braking problems in the press, including reports from Japan...
http://news.yahoo.com/s/ap/20100203/...n_toyota_prius

I'm wondering if there might be a generic problem developing over time with regenerative brakes. Anybody know more?

It's a software issue, and software does not develop problems over time; it does the same thing over and over.

Based on what I've read and my own experiences with some Toyota vehicles having the braking anomaly, the issue is with the ABS software, not the regen software. The ABS can kick in unnecessarily when the car hits a bump or pothole during continuous braking. This causes the brakes to alternately let up and grab, reducing the car's deceleration rate, which can feel like acceleration to the driver. After a moment, the ABS system cuts out and full braking resumes. Pressing the pedal harder during the ABS mode will increase stopping power. Alternatively, if the driver lifts up on the brake pedal momentarily and then presses it again, this will also cancel the ABS.

You can test your car to see if it has the issue by finding a safe area with a pothole and driving about 20 mph, then start braking moderately with constant pedal pressure a couple of seconds before you hit the pothole. Maintain the constant pressure during and after impact with the pothole. If the ABS kicks in for a second or two, then your car has the issue.