braking in reverse

[garygid]

THE BACKUP BUG - UNEXPECTED ACCELERATION

Just yesterday, my Prius-III backed up with sudden unintended acceleration, with my foot only on the brake pedal. No, the accelerator pedal was not "stuck" or being touched in any way. The parking spot was level.

I recognized what was happening because it happened once before, just over 2 months ago, just a few days after I got the car, when I was backing out of an inclined driveway. Perhaps insignificant, but both times, I had a passenger in the passenger seat.

I suspect that some unusual element of the timing of turning the car ON, and shifting into Reverse, and possibly the internal state of the computer and the hybrid power system combine to produce this "abrupt" reverse acceleration as I am gently easing off my foot pressure on the brake pedal. Others describe this as an annoying "Abrupt Braking", and the abrupt braking effect does occur, but only in response to the much more DANGEROUS "unexpected, unintended" reverse power (acceleration), to stop the car motion. No matter how gently the brake is eased further ON to stop, the stop is "abrupt", not smooth.

Yes, in this case pressing the brake gently, just a little, stops the car, but with a big "Jerk" (the Abrupt Braking effect). Then, shifting into Neutral and then to Reverse again "resets" the software so that further backing is the normally expected gentle movement of the car.

However, the unexpected "jump" backward (due to the unexpected power and acceleration) might have caused an accident, crashing my car into anything behind it. This is DANGEROUS.

And, after the crash, who would believe me when I said, "The Prius-Backup-Bug did it, not Me!"?

Sincerely trying to help Toyota have a better Prius,
Gary ..., PhD
Prius-III + Nav, made July 2009 in factory "5"

[macdonald]

I have experienced the brake grabbing problem on more than one occasion. When it happened yesterday I was backing out of a parking space where I could not see behind me well, and had to move very slowly.