Not so spontaneous, intended acceleration - Toyota Yaris Forums

Loren · 03-15-2010, 04:23 PM

It's a "learning" system. You may want to try resetting it to default so that it can learn YOUR driving habits.

The throttle pedal is definitely not linear. Think of it as a "demand" pedal. Where you place your foot and/or how quickly you move it are the inputs that the ECU uses to assess what you want it to do. It then uses that input and many others to determine how much to open the throttle, how to set the valve timing and ignition timing, whether to go rich (open loop) or use the O2 feedback to keep the mixture stoich, etc.

Most people complain about the opposite problem, the DBW system is not sensitive enough. And maybe that's what you're feeling? It's not sensitive to a small input, so you give it a larger one... which it then responds to.

Give it time, it should learn you and you will learn it... you'll get used to it.

Yaris Hilton · 03-15-2010, 04:40 PM

I've noticed a trend in recent years to make throttles very quick responding in the first bit of travel. It's a cheap way to make drivers think a car is very powerful and speedy. "It wants to leap ahead when I barely give it the gas!" If they have to push the pedal halfway down to get the same response, average drivers will conclude the car lacks power.

sbergman27 · 03-15-2010, 04:49 PM

Quote:

Originally Posted by Loren

It's a "learning" system. You may want to try resetting it to default so that it can learn YOUR driving habits.

My accelerator pedal is heuristic!?!?!?!?!?!?

Oh my. I was not expecting that.

What's the easiest way to go back to the defaults? I've driven 2-1/2 weeks and about 6,000 miles (yeah, I drive a lot) and have not noticed any change in its behavior.

-Steve

Edit: The *very* first bit of pedal travel does not seem to get any response at all, so I push it a little farther (not much) until I do get a response. When it kicks in, that's when it seems overly sensitive. Is that what you are referring to?

Yaris Hilton · 03-15-2010, 04:57 PM

The only learning behavior I've noticed is in transmission shift points. It trains very quickly, usually in a day's driving. No special action is needed for resetting, it adjusts to your driving style as you go. Thrash it and it'll wind up farther before shifting and downshift quicker. Drive it like a hypermiler and it'll lug along shifting when it really has to.

Altitude · 03-15-2010, 04:58 PM

Quote:

Originally Posted by sbergman27

My accelerator pedal is heuristic!?!?!?!?!?!?

Oh my. I was not expecting that.

What's the easiest way to go back to the defaults? I've driven 2-1/2 weeks and about 6,000 miles (yeah, I drive a lot) and have not noticed any change in its behavior.

-Steve

Disconnect the battery for a period of time (just how long I'm not sure as I've seen many different values mentioned.)

FWIW - Mine is a manual and I find just the opposite in that I have to goose it a bit to avoid stalling when letting the clutch out. I've considered doing the reset and stomping on it for a while to see if the ECU adapts to the new style. Let us know how your experiment works out.

03-15-2010, 04:23 PM	#1
Loren What? Drives: 2007 Yaris LB Join Date: Nov 2008 Location: Safety Harbor, FL Posts: 1,006	It's a "learning" system. You may want to try resetting it to default so that it can learn YOUR driving habits. The throttle pedal is definitely not linear. Think of it as a "demand" pedal. Where you place your foot and/or how quickly you move it are the inputs that the ECU uses to assess what you want it to do. It then uses that input and many others to determine how much to open the throttle, how to set the valve timing and ignition timing, whether to go rich (open loop) or use the O2 feedback to keep the mixture stoich, etc. Most people complain about the opposite problem, the DBW system is not sensitive enough. And maybe that's what you're feeling? It's not sensitive to a small input, so you give it a larger one... which it then responds to. Give it time, it should learn you and you will learn it... you'll get used to it. __________________ ----------------------- Loren@InvisibleSun.org -----------------------

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03-15-2010, 04:40 PM	#2
Yaris Hilton Half a Bubble Off Plumb Drives: 2009 Yaris Sedan Join Date: Mar 2009 Location: Bristol, Tennessee, USA Posts: 1,593	I've noticed a trend in recent years to make throttles very quick responding in the first bit of travel. It's a cheap way to make drivers think a car is very powerful and speedy. "It wants to leap ahead when I barely give it the gas!" If they have to push the pedal halfway down to get the same response, average drivers will conclude the car lacks power.

03-15-2010, 04:57 PM	#4
Yaris Hilton Half a Bubble Off Plumb Drives: 2009 Yaris Sedan Join Date: Mar 2009 Location: Bristol, Tennessee, USA Posts: 1,593	The only learning behavior I've noticed is in transmission shift points. It trains very quickly, usually in a day's driving. No special action is needed for resetting, it adjusts to your driving style as you go. Thrash it and it'll wind up farther before shifting and downshift quicker. Drive it like a hypermiler and it'll lug along shifting when it really has to.