Toyota Calls Automatic Power Reduction a Safety Feature The Toyota Prius is known to occasionally shut down its hybrid engine system for no apparent reason, wear tires quickly and unevenly, even drain a battery dry when parked for an extended period.
But here's one of the oddest Prius stories on file at ConsumerAffairs.Com:
"When my car is on any kind of slick surface that causes one of the front wheels to slip, ALL power to the drive system is stopped," wrote Christopher of Reston, Virginia.
Christopher said he first experienced the problem with his Prius "on a sloped gravel driveway in July but discounted it as a temporary thing."
Then the snow fell.
"This past weekend I was on a snow-covered road with about an 8- to 10-degree grade. Driving at 20 miles per hour, one tire began to slip on the snow and the car came to a stop. The wheels then refused to engage, because one would slip a little, regardless of throttle position," he wrote.
Christopher tells ConsumerAffairs.Com that he "had cable style tire chains and installed them properly on the front wheels and tried again. Still, a tire would slip on the 4 or 5 inches between the cables and the car would refuse to move."
Ultimately, he said, the only way to get the car up the remainder of the hill was to get out and push while his son put a foot gently on the throttle.
His Toyota service manager told Christopher that he was able to duplicate the symptoms on a level snow covered surface and apparently achieved the same results with two other Prius cars that were in the dealership fleet.
But after reporting the problem to Toyota, the service manager told Christopher that the Prius was operating as designed.
Christopher said that he "will consider this vehicle unsafe for road use under any snow or ice conditions and frankly feel that if all Prius vehicles are designed to do this someone ought to look into the situation to try to force Toyota to modify the design."
Not a Safety Problem
Toyota spokesman Bill Kwon agrees that the traction control systems in the Prius could impact performance in snow conditions but says that is not a safety problem.
"Prius has TRAC (traction control) as standard equipment," he said. "The purpose of traction control is to helps prevent wheel spin and minimize slippage of the drive wheels by applying brakes and/or reducing engine power."
Kwon points out that an 8 to 10 degree grade "is a fairly steep grade and combined with snow would cause a loss of traction which will activate the traction control system and therefore reduce or cut power."
"A vehicle without TRAC in those conditions," Kwon adds. "would probably just start spinning in place and eventually spin out of control. In my opinion, it's better to have the vehicle stop then to have the wheels spinning and out of control."
