Here's what I do about braking issue...

Woooohhhhhhh!!!!! What brakes??? The media hype has hit me. I was asked today if I was sure it was safe to drive my 05 Prius. I told them, that I just take one mile at a time, and do the best I can with great caution.

How many Prii must be looked at with suspicion? Anyone notice other drivers giving you more room on the road, yet? What a farce.

 

If you are braking moderately, then you are not using much friction braking so you don't have to worry about your friction brakes wearing out, as long as the traction battery SOC gauge is less than 8 green bars. Once the gauge becomes full, you may hear the engine speed up (kind of a quasi-B mode) and the braking load will shift more to friction braking so that the battery doesn't become over-charged.

Therefore, what I do when going downhill is to leave the shift selector in D until I see 8 green bars. At that time, if there's substantially more downhill terrain to cover, I'll shift into B.

If your driving conditions are such that you can't safely control your downhill speed when the shift selector is in D, then go ahead and shift into B and don't worry about it.

 

Hmmm.. Most of my cars are FWD!! I can take 1 of 4 FWD cars in my driveway right now and show you there is a difference. We have an '06 Camry, '04 Mazda MPV and '03 Jette and neither of them will produce enough braking pressure in low gear to to make the do a 180. The specific situation that I created and then recreated was, entering a snow covered downhill at 10-15 mph, letting go of the gas peddle while the shifter is in "B", will brake the wheels enough to bring the nice person end around!! On my other Front Wheel Drive vehicles, this is not the case!! Now I can see if in my other FWD vehicles I entered the downhill faster and then dropped it to 1st gear(if they even have it as an option), that might do force a 180?? But in the Prius, going very slow into a snow/ice covered downhill in "B", and releasing the gas pedal but not applying the brakes, will force a 180. Now, I just put snow tires on, and we are supposed to get some snow in the next couple of days. I'm hoping to go and try it and see if it makes a big difference. I'm betting it will. I'll let you know :hug:

 

How many amps and volts does that blue line represent?
Where does the energy come from to spin the engine? You can hear it spinning can't you?

I think you need to be brave and somewhat foolish to challenge Johns knowledge of the HSD, have you seen the research he has done? John is one of, if the most respected and knowledgeable people with regard HSD on the face of this earth outside of Toyota.
If John says it's true, 99.99% probability it is.

 

Perhaps the poster was not aware of John and his site. I would never challenge Johns knowledge of the Prius and have great respect for him. Saying all that, I have come down off the Sierra Nevada Mountains numerous times and often use B mode, regeneration occurs! Between D, B and neutral this happens four times. MPGs of 60-70mpg are normal, with constant regeneration/degeneration of the SOC. I use N when possible if the SOC has reached solid green. As for experimenting on ice with B mode...perhaps, on a safe location, never on the highway. But the posters information is useful.

 

"I don't know if this is a "good" solution or not to my braking issue with my 2008 Prius"

What braking issue? According to Toyota, only the gen III Priuses have a braking issue.

 

B mode uses regenerative braking when possible. The point that many people miss is that B mode intentionally throws away some of this regenerated energy. When you switch to B mode, you are telling the computer to use the ICE as a big energy trash can, tossing out surplus energy. You want to use B mode when you know in advance that the HV battery will charge to its high limit.

Some drivers also like to use B mode in long descents because it simplifies braking control. Rather than shifting back and forth between the gas and brake, with B mode you can often keep your foot on the gas pedal while still maintaining speed control. When you do this, you accept the fact that you will be discarding some energy and consider the ease of control worth the small cost in lost energy.

Tom

 

From past posts here, I have learned that B is not normally used, and wastes gas as regen is lessened, a lot. I tried it once on my 07 when new, never since, no need. Also I have been instructed here the regen alone normally brakes the car, only when a certain higher brake pressure is applied does the friction brake add resistance, or below 9 mph. My friction brakes apply at 6 mph for some reason. So if a Prius is driven like it ought to be, there is little use of the friction brake. If one is driving like all the SUV's around them, that is racing from stoplight to stoplight and slamming the brakes hard, then it seems the design concept of the Prius is diminished.

 

It doesn't really help, unless you do a lot of mountain driving. Regenerative braking is why your pads are lasting, and you get regeneration with or without B mode. As for liking the feel of B mode, that's a personal preference, so you won't get any argument there.

Tom

 

If memory serves, Mary has a Gen II Prius. To date, there is no recall or service upgrade or whatever for Mary's brake system issue. If she is lucky, the service advisor will take down her issue description and forward it up the food chain to Toyota USA. Worst case, she will be told that there is nothing that is available for her issue and she then has to continue to suck it up and try to mitigate the issue as she has had to do to date.

Either way, I would recommend she file a report with NHTSA if she wants it to get serious attention.

Here is a link to ODI's site for safety issue reporting: Office of Defects Investigation (ODI), File A Safety Complaint

 

Hi Mary,

It sounds like you still have the original equipment tires installed. With 25K miles on the car and given your complaints about lack of traction, I am sure your tires are quite worn.

6/32" is the minimum safe tread depth required when driving on snow. If your tires are Goodyear Integrity, they are not safe on snow even when new. What are your tires' tread depth?

It is "normal" for the Prius yellow skid light to come on, if the car is equipped with worn tires. However, you don't have to tolerate that, nor do you have to shift into B all the time. Just buy a decent set of winter tires to deal with the snow, then buy a set of good all-season tires when the snow is done.

If you don't have any warning lights on, I don't see the point of your Toyota service visit. You'll probably have to pay for an hour of labor, and all the tech will tell you is that the tires are worn and the brake system is fine.

Use that money to help fund a set of new tires, and you should notice a big improvement. Good luck.