Traction control?

I believe the Dr Prius app can do that, but you have to be very careful with your driving. The Prius transmission is not known for being able to take the jolt of going from the spinning wheel to good traction without damage.


iPhone ?

 

i think there is a way to put it in maintenance mode or something to disable it on gen 2. search the old threads

 

If they are really new you can have them studded, studded snows on the prius make it a winter beast, had studded snows on a gen2,3,4 and now a prime, winter beasts, the gen2 is terrible without studs on snow and ice, turning off the traction control is a good way to snap a drive axle, expensive, studs, cheap.

 

They shouldn't of ever called it traction control, because when it comes to the traction it doesn't increase traction or control it, it simply protects the high-torque of your electric motor from damaging the drivetrain by shutting it down whenever the wheels spin. And while many people have mentioned disabling it on here over the years, no one has ever mentioned how to reinforce the drive train so disabling it doesn't destroy the car.

 

For the Gen 1 Prius (2001 - 2003), that would be a complete description. The Gen 1 really only had a feature to dial back the power when wheels spun, and it was really there to protect the transaxle more than anything else, but they tried to spin it as a traction control feature.

Starting with Gen 2 in 2004, and ever since, it is a real traction control; it does not just blindly dial back power output, it will detect which wheel is slipping more and apply the hydraulic brake to that wheel, so that the slipping wheel is slowed, and power that was being wasted at that wheel is diverted to the wheel that has more grip.

This explanation is from page TH-47 of the 2004 (Gen 2) New Car Features Manual:



You can see that the system is designed to allow some wheel slip: the drive wheel speed is allowed to stay slightly above the true vehicle speed, which can be helpful on some surfaces like snow, but it doesn't allow the kind of excessive spin that just wastes all the traction you've got.

If you set out to make a video demonstrating exactly what that graph shows, you'd end up with one just like this one here:

... where the driver is giving a steady go-pedal input, the car is continuing to pull with the wheels, but always making sure not to spin excessively and destroy traction.

-Chap

 

My 07 Touring does not do that. It simply shuts down the entire drive train, pauses briefly, and repeats the insanely annoying process.


iPhone ?

 

Your 2007 is a Gen 2, and the material above was quoted from a Gen 2 New Car Features manual, so this forces an awkward comparison of credibility between your reporting and the Toyota documentation (along with available video evidence). I don't know you very well, but I've often found the Toyota books accurately describe the cars they build. This would be like Toyota completely making up an algorithm that they never really programmed into the ECU. That would be awfully weird, and not anything I've seen with them before.

The video clip above was of a Gen 3, so perhaps not directly applicable, but here's one of a Gen 2 behaving as documented:

One thing that might be safe to conclude about the Toyota TRAC is that it doesn't complement every driving style equally well, and might seem to behave "insanely" relative to a particular driver's expectations and inputs. There was more on that a couple years ago here.

-Chap

 

I agree with @nssdiver Same issue in my '07 as well... When traction control light goes on because of wheel slippage from uneven pavement & worn out struts while making a turn out into oncoming traffic the electric motor shuts down entirely for about 1.3 seconds, which usually leads to horn honking from the people who felt I cut them off when if I had gas and electric running they would of never have had to change their speed.

I'm certain that when this happens the electric motor shuts off completely because I experience that type of acceleration with engine only when testing Gen2 Prius with bad hybrid pack and computer shuts off use of the electric motor. Perhaps this doesn't happen as much when the Gen2 Prius is brand new and the system doesn't work so well after 100K miles with worn out struts?

But to say first hand experience of more than one 2007 Prius driver is not as credible as Toyota promotional literature, that's not fair. I've talked to people that sold their Gen2 Prius because this horrible design sacred the heck out of 'em one too many times when they lost power when they needed it most. So I understand why Toyota would be super eager to claim that they addressed it when they improved Gen 1 design in the Gen2, but the claim is just a "claim" not a "proven claim" via first hand experience and professional reviews.

Meanwhile Tesla says they test slipping wheels on a frozen lake bed and their systems can adjust to prevent wheel slippage 1000 times a second with very little loss of power so you can keep accelerating and not even notice a loss of acceleration. And all Toyota can offer is a total shut and restart of that motor in a painfully long 1.3 seconds when vehicles are racing up behind you? What a joke! All that being said, I love my Prius because of good gas mileage and reliability at a price I can afford.

 

That could afford to be unpacked a bit. It is unfair to misrepresent what someone else has said, or the nature of a source, and some of each is going on in the above quote.

• I didn't (and can't) make any universal, speaking-for-others, judgement of credibility. When nssdriver chose to post a direct contradiction of the information from Toyota that had just been posted above, I pointed out that readers facing flatly contradictory information are forced into making a credibility assessment. Readers might not all make the same credibility assessment, but the choice to post something in the form of a flat contradiction does force every reader to make one, so a poster has to understand that will happen, whether it feels fair or not. I also described how my assessment would be likely to go and why, but that's my call, based on my experiences around PriusChat.
• To describe the New Car Features manual as "Toyota promotional literature" is a misrepresentation. The NCF is part of the technical documentation of the car, found on TIS along with the Repair Manual, which it logically precedes. It is the description of the systems in the car, what they are for, what they do, and how they do it. The descriptions are detailed and include the inputs, outputs, network interconnections, etc. These details can be verified in the other TIS volumes like the wiring diagram, and even by examining the actual car. If you think you've found something the NCF says is in the car, but that is "just a claim" until a reviewer says it's there, your evidence would be super interesting to see.
• "First hand experience" is only first hand experience to the person who has it. As soon as you, or I, or anyone, posts a "first hand experience" on PriusChat, what that is to every other reader is a "claimed experience by someone I may or may not know well." Most PCers who have been around for a while probably have a bunch of other PCers whose handles they recognize, and have different degrees of confidence they would invest in claimed experiences coming from those posters, and have sort of a different, fallback level of confidence for other PCers with less of a track record.
• Those levels of confidence in other people's reported experience don't just have to do with thinking the other person might be honest or deliberately lying. There might be some posters who really do that just to troll, but more of the time there'll be no question of someone's honesty or good intentions, but more questions about whether someone's reported "experience" could include conclusions they jumped to with some of the evidence ungathered or assumptions untested. Different posters develop different track records for that kind of thing.

For times when a judgement of credibility might feel unfair, there are ways to handle discussion that leave more options open. Following some posted information with something like "hmm, that didn't feel like what was happening to me in a situation X that I was in under circumstances Y and Z, I wonder what accounts for that" could end up leading a discussion into a better understanding of how the system could be as the manual describes but still feel like something else is happening in circumstances Y and Z.

But posting flat contradictions of information that's straight from the manuals doesn't leave most of those options open; it just kind of begs an immediate relative-credibility judgment that isn't guaranteed to go in the poster's favor. (Especially when there's video available where what the manual describes can be seen happening.)

-Chap

 

So you're saying you've never driven a Gen2 when the traction control light came on and you've never lost power at a critical moment when accelerating into traffic? Not even once? Yet you deny the experiences of more than one person who has written at length about how those experiences are real? You're in the wrong forum bro... You should find a church and bible and leave us alone. We're trying to solve problems in this forum not deny problems claimed is a form of heresy to what the scriptures say...

 

What causes traction control to have greater than normal latency returning full power to the driveshaft?

A lack of traction from bald tires and exhausted struts & springs is first thing to look at, but what of tweeking / changing how traction control responds in the first place? Is their a better spoof than just turning traction control off entirely?

 

Glad to find something to agree on.

Gen 2 TRAC has been around more than fourteen years now, and still people do continue to experience (and sometimes record on video) behavior like you're describing. That's a problem, and it would be good to help people solve it.

At the same time, we don't have to be faith-based about the service literature that explains how the system works, because we also have first hand experiences of it working that way, and video evidence showing it. So pretending the documented behavior is just some kind of promotional vapor won't cut it. That's misinformation, and doesn't help solve problems.

So what does this have to do with denying anybody's experiences? People can be different in how carefully they report their experiences. For example, Alice might say "I've had this first hand experience where I was driving in such-and-such conditions and I gave such-and-such pedal input and this is what happened." Bob, in contrast, might say "my first hand experience is the car doesn't do what the manual says at all, it does this other thing instead."

Alice and Bob both had real experiences. Alice is describing hers in a more useful way, where Bob is mixing together what he experienced with a conclusion he jumped to about it, where the jump is too far for the evidence. Pointing that out might feel to Bob like "denying" his "experience", but it isn't; it's more about reminding him to separate the experience part from the assumptions, something Alice already did on her own.

To be interested in solving a problem is to be interested in questions like "what might be going on that's different between cases that look like video A, and those that look like video B?" Even better are questions like "does that suggest anything I could do differently so I would more often get results like B than like A?" ... 'cause that puts the driver in the driver's seat and makes better outcomes possible.

Fourteen years has been a lot of time for asking and answering those questions. There's good information in the fifth paragraph of hobbit's writeup, and it's been there since 2005.

Now, back to Alice and Bob, probably Alice would be happy to be pointed at that write-up and get ideas she could practice, leading to better satisfaction with her traction control. Bob might be much happier to be humored and just told "yup, you're right, it just doesn't work like Toyota says at all, it only ever works like you think." But other than maybe being happier, how is he helped by that?

-Chap

 

This gave me thought- are there really two separate programs running in the later models? One for transaxle over-torque protection and the other for traction control, with only the latter one having a user override switch?

Also- regarding the plot of wheel revs to vehicle speed given a steady 75% throttle input: what happens when you jam the throttle to full? I'd love to see the corresponding plot and video for that case.

 

Well, as hobbit described it in '05, flooring the accelerator "makes it take a huge dig with the wheels and then immediately back off power while flickering the little fishtailing-car icon, and it'll keep uselessly doing this over"

... which sounds like a familiar refrain, suggesting that the corresponding video(s) for that control input would be the various "Prius TRAC sucks" clips you can find on youtube ...

-Chap

 

having driven my 2nd gen 8 months of the year in snow, I can attest that the car does cut power. I understand how traction control systems that brake the spinning wheel work. In theory they should work through an open differential, in practice it is completely down to the programming of such systems and Toyota doesn't do a very good job, Subaru does an excellent job on the other hand. There have been situations when there was no traction at either wheel in 8" of snow and the ECU would not allow any wheel spin at all. No need to write an essay about philosophy or psychology on the subject, it can be as simple as a line of code in the traction control computer.

If the spin (wheel speed) is greater than a certain velocity, cut power for 1.0 seconds. If less, apply brake on the spinning wheel for 0.3 seconds, etc.

 

This awesome... Thanks for posting this... It really is a simple software issue and if they weren't so full of their own gluttonous obsolescence they'd have over the air software updates based on region you live in and weather patterns and forecasts for the upcoming months. Of course serving customers doesn't really matter until no one wants to buy your cars.

Any other car maker have a waiting list to buy a car other than Tesla?

Lol... Toyota may of survived the last demise of the auto industry a decade ago better than any other, but their unwillingness to adapt will bankrupt them just as fast as the rest of Detroit when the next downturn comes. They've done nothing to advance the technology for way too long!