Very Strange Lexus Crash

Many people state the first line as if all steering will be lost. The Edmunds article is partially correct in that only the assist stops, not the steering itself.

But I spent my first decade of driving in two cars that stalled anywhere and anytime they wanted, no matter how inconvenient it was for me. The first did so frequently, the second much less so, but still often enough to be annoying.

Sure, it takes considerably more force to steer when stalled. But I remember having difficulty steering only at parking lot speed, not street speed. Is my memory faulty from age, or are modern power steering systems that much harder to steer when stalled, compared to '63 and '78 Fords?

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This case seems strange enough that I must wonder aloud whether it was intentional. That is the reason for the domestic violence question. If a big city police chief near here (Tacoma) can do it, so can anyone else.

 

At freeway speeds, the power steering is not doing a whole lot regardless of the age of the car, so you're memory is not failing you. The only limitation would probably be if you tried sudden wheel movements at speed, then the lack of assist would result in slower turn in and having to use much greater force. But you can still steer.

Something is indeed strange about the whole incident. I am nearly 100% certain that either the act was intentional, or the driver simply lost it and was unable to think with any clarity. The chances of the vehicle itself being to blame are incredibly low, nearly impossible. That goes for any modern vehicle not just this one.

 

Improper floor mats have been implicated in many crashes. There have been TSB's issued that deal with that, and even my FJ Cruiser has a warning about improper floor mats leading to a loss of control and a crash

At highway speeds, if you press in the power button and keep it depressed, after about 3 secs the Prius will power down, shift into N. Folks who operate a car with a push button start system MUST know the proper procedure to kill the car, in an emergency

Of course, in a conventional vehicle, you turn the key to off, except most folks turn it too far to Lock, and the steering column locks up. That can also cause a crash

 

Isnt the Prius steering electric?
What happens if the power is turned off while driving?
Can it be steered?
Also about brake fluid boiling.
Isnt the emergency brake fully mechanical not hydraulic?

 

Power steering generally has variable assist depending on what gear you're in or how fast you're going, with maximum assist at low speeds and less assist the faster you're travelling. You don't need much assist to change lanes, and indeed you don't want assist because an overreaction from the driver would just spin the car out.

"Directions and amount of assisting power are determined by signals from the torque sensor built into the steering column assembly and by the power steering ECU, and controlled in accordance with
vehicle speed. As a result, steering effort is controlled to be light during low speed driving and moderately high during high speed driving."

-- Gen 2 Prius service manual, section PS - Power Steering.

The Prius power steering control ECU gets its speed information from the Skid Control ECU, which reads it from the wheel speed sensors. (The same information drives the speedometer.)

So you don't notice a failed power steering at high speeds because it's not providing much assistance at those speeds when it is working.

 

Electric assist, same as the new Corolla. The brakes are electric assist, same as the FJ Cruiser

Yes, it can be steered, but the wheel effort may be a lot higher

If you don't maintain your braking system, old brake fluid can boil fairly easily. With vehicles I had pre-Prius, I'd flush the brake fluid every 2 years. You'd be surprised at the condition of brake fluid after sitting for 2 years

Otherwise, for brake fluid in good condition, you're really have to smoke the brakes before the fluid boiled. That is, the pads would probably melt first

The parking brake on a 2004-2009 Prius works off the rear drum brakes, and is fully mechanical

 

I should clarify: with my Prius I also had the brake fluid flushed every 2 years, but at the dealership. With the Prius, a brake fluid flush and bleed is clearly not a DIY task