400h's Ice Seems Be Powering Wheels Even When Foot Is On Brake

tommy275 · July 6, 2007

i've been noticing an odd phenomenon with my 07 400h. this started happening at about 8k miles or so...

sometimes when i'm at a complete stop, with my foot firmly on the brake, the ICE kicks in and, according to the display screen (and also my own sense of what's happening), it seems as though it's trying to drive the front wheels to make the car move. i would think that the ICE would kick on if it needs to recharge the battery or run the A/C, but it seems odd that it's clearly trying to set the car in motion. the same type of behavior is occasionally noticed if i'm in slow traffic on a heavy incline, using the break pedal (no gas) to control the speed of the car: i can feel the ICE trying to propel the thing forward, even though i'm just using the break to slow down and no gas pedal whatsoever.

of course, the dealer has no idea what i'm talking about and didn't even understand what i was saying when i explained the symptoms. they also told me that the vehicle is primarily a rear-wheel drive, which i believe is flat out wrong. maybe they're right on that though.

has anyone else noticed this? or am i really special.

richard4u · July 6, 2007

i've been noticing an odd phenomenon with my 07 400h. this started happening at about 8k miles or so...
sometimes when i'm at a complete stop, with my foot firmly on the brake, the ICE kicks in and, according to the display screen (and also my own sense of what's happening), it seems as though it's trying to drive the front wheels to make the car move. i would think that the ICE would kick on if it needs to recharge the battery or run the A/C, but it seems odd that it's clearly trying to set the car in motion. the same type of behavior is occasionally noticed if i'm in slow traffic on a heavy incline, using the break pedal (no gas) to control the speed of the car: i can feel the ICE trying to propel the thing forward, even though i'm just using the break to slow down and no gas pedal whatsoever.

of course, the dealer has no idea what i'm talking about and didn't even understand what i was saying when i explained the symptoms. they also told me that the vehicle is primarily a rear-wheel drive, which i believe is flat out wrong. maybe they're right on that though.

has anyone else noticed this? or am i really special.

You are either special or something is wrong with your 400h . When i am stopped and monitoring the power,if i dont push hard on the brakes i can see the power leaving the battery , but if i push a little harder = no power used, did you change the way you brake? are you so used to a light foot on the brakes that you actually are doing this phenomenpn??

wait and see other replys. good luck Richard4u

tommy275 · July 6, 2007

actually, i misstated the issue. it's not the ICE, but rather the battery driving the front wheels as i'm braking or after i'm stopped (as you describe basically). i don't think i've changed the way i brake. i drive through the same tunnel every morning, and there was definitely a point at which i started noticing this (both in the amount of pressure it took to brake and the display on the NAV). then again who can be certain about these things.

silvercorvette · July 7, 2007

First of all the dealer is wrong, I have All wheel drive but on non AWD car they are front wheel only they add the AWD to a front wheel drive car by throwing an extra motor in the rear so the car was designed as front wheel drive with a rear electric motor on all wheel drive vehicles. I have also noticed that if I don't keep firm pressure on the brake the car moves. The electric indicator on the NAV screen shows that the battery is moving the car. The solution is simple keep firm pressure on the brake and the car won't move. To me it isn't a big deal it is just the way the car is designed. Any car with automatic transmission will do the same thing the only diffrence is that you have to press the brake pedal a bit harder with a hybrid

wwest · July 12, 2007

First of all the dealer is wrong, I have All wheel drive but on non AWD car they are front wheel only they add the AWD to a front wheel drive car by throwing an extra motor in the rear so the car was designed as front wheel drive with a rear electric motor on all wheel drive vehicles. I have also noticed that if I don't keep firm pressure on the brake the car moves. The electric indicator on the NAV screen shows that the battery is moving the car. The solution is simple keep firm pressure on the brake and the car won't move. To me it isn't a big deal it is just the way the car is designed. Any car with automatic transmission will do the same thing the only diffrence is that you have to press the brake pedal a bit harder with a hybrid

I think I have read somewhere that what you describe is being done intentionally so as to give you the expected "feel" of a normal car with an automatic transmission.

On the other hand it may be part of the current ongoing effort by the industry at large to remove some of the hazards of FWD. Engine "drag", or engine compression braking on the front wheels can most definitely interfere with the proper operation of your anti-lock braking system. The "rise" in drive torque to the front wheels during braking may very well be in an effort to protect you from loss of directional control should the roadbed happen to be slippery.