Why no Trac Off button

I think it is to prevent damage to the hybrid drive train.

 

As pointed out above, it is to prevent damage to the HSD. However, that begs another question: How can the Lexus HS250h do it without the same risk of damage?

Tom

 

Because the Lexus is perfect. The Toyota is not. At least according to their ads... "in pursuit of perfection".

All bad jokes aside, very interesting question... time to start coming up with crazy theories until someone intelligent comes up with the real answer. I'll start...

The Lexus might have better tires and with trac control OFF, the tires will still grip...

The Lexus might have extra bolts and parts holding the HSD so it will withstand the abuse...

The Lexus trac-off may not a true 100% trac-off...

...

 

I don't really understand how Traction control protects HSD. Differential may be. Is it because differential pumpkin is also present in same housing?

Traction control as I understand will help in wheel digging itself in mud or snow pile. It will also help when one side hydroplanes and losses contact with ground.

But as far as transmission is concerned output speed of transmission is average of two wheel speeds. Why not an override as it exists in most cars and in Lexus HS250h ?

Does the unofficial override of inspection mode work in gen 3 the same way as in gen 2?

 

ok sir you debunked 2/3 of my points...

 

With the Gen II Prius such as yours, traction control only controls the power output. When either drive wheel spins significantly the traction control system cuts the power to both wheels. It will not help with a wheel digging in, or with hydroplaning, other than cutting power.

The electric motor on the Prius gives it a lot of low end torque. Without some sort of traction control system it would be easy for inexperienced drivers to spin the drive wheels. Spinning drive wheels present two possible problems: 1) Overspeed of critical parts, and 2) Shock loading if and when the drive wheels grab. Either of these can destroy your HSD.

The Gen III Prius employs selective braking in addition to power modulation. In this respect the Gen III system is true traction control which will help you when only a single tire slips.

Tom

 

the lack of a tcs off button is a safety hazard in my mind, one of the worst decision on the car

 

Sometimes if it just wouldn't have stopped both wheels quite so soon you could make it, but once your stopped there is no hope except calling for help. Unfortunately I was 600 miles from home 30 miles from the nearest town and totally without cell phone coverage. I was on my way to Reno last month and decided to stop have lunch and go for a hike down by the lake.

Fortunately an angle of mercy came by in the guise of a Washoe County Deputy and called a tow truck on his radio. Tow truck showed up in about 45 minutes pulled me out using the rear tow hook, no damage except to my ego. Tow truck came from Fernley NV, real nice guy, only charged me $180 which State Farm paid no questions ask.

Sorry about the quality of the photos, used cell phone camera.

 

I recently took a 2010 Toyota Venza AWD V6 for a spin. It has a Trac Off button

 

Traction off isn't going to help you in that instance

 

Correct, it would only help if you knew ahead of time you were entering an area where you might have trouble. If I had known that I wouldn't have gone there to start with. It might have helped if the traction control had allowed some wheel spin instead of stopping both wheels completely. What did help was having to get towed out because I'll be more careful next time, I hope.

My BMW had a very useful traction control system. Full on it limited the engine to about 1500 RPM, you could turn it 1/2 way off so it still used the brakes to stop one wheel from spinning more than the other but allowed the engine to rev to about 3500, the next push of the button turned both stability control and traction control off. But I think that car has a very strong (and heavy) drive train, you have to give some things up for efficiency.

I need to watch for low traction areas in the desert, Prius doesn't make a good dune buggy. Maybe it's time to look at a RAV4 or an FJ Cruiser, or the equivalent from Honda, to go with the Prius?

 

Which is why I said:

Tom

 

If it's such a "safety hazard", why are people driving these vehicles? Why not get something you feel "safer" in? It's not a car for everyone and every situation. Maybe a bit of discretion when driving in limited traction areas. it certainly does the job for 95% of the driving out there.

 

Use better tires. The factory ones leave much to be desired. I noticed a big improvement with my 2004 in Minnesota.

With my 2010, you'll notice a big improvement... even with the factory tires. The newest generation eliminated the need.
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