All,
Five or Six times now since owning my FEH 4x4 (for 10 months), when stopped at lights on the same hill the slight forward torque from the electric motor did not get turned on and the car started to drift backwards down the hill very quickly like it was in neutral, my quick reactions have stopped this so far, and i had to put my foot on the break and accerator at the same time to pull off without rolling back a fair distance.

re my other post i had the car serviced today and they tell me this is 'Normal behavior' they ran a 'Test' when clearly this isn't. Last week it happened to my wife and quite frightened her. I suspect she will now never drive it again......

Has this occurred to anyone else? Is this some kind of intermittent senor problem? Other than having an accident how do i convince my dealer to take this seriously?

Thanks
Dave

i've had my car do this and i thought it was rather interesting. i assumed that if you're completely stopped at a light, the car basically *is* in neutral. as soon as you lift off the brake, gravity would take you backwards or forwards depending on the slant of the road.

i'll leave the engineers here to technically explain this one if i'm off base...

There's no real 'neutral' in the PSD/eCVT/HSD/THS systems, the traction motor cannot disconnect from the output shaft/wheels. It's strictly software that takes care of deciding if it should apply power to the motor after you take your foot off the brake pedal. Someone else had mentioned that their FEH would start rolling forward quite fast upon letting his foot off the brake at random times, so I think there's some flakey/buggy programming showing up that Ford has yet to acknowledge and make a patch for.

2001 Prius Photos       2005 Prius Photos
'97 Prius Simulation Prius inner workings

It may be the case that you are not releasing the brake pedal completely enough for the software to decide to turn the "creep" function back on.

In any case, it's best practice to not rely on the "creep" to hold you on a hill as it consumes power while the brakes do not. There is also a possibility (unlikely though it is) that holding on a steep incline long enough could cause an overheat to be detected, which would result in shutting down the motor...