I have to assume this is me and not my 2011 HL but I thought I'd ask here....
Every once in a blue moon, I find that after a full stop at a light, I end up creeping forward slowly. I don't think I ease up on the brake but you never know. It takes a small but definite movement to the brake pedal to stop again. I try to pay extra attention to how I hold pressure on the brake pedal but (of course) it never happens when I am paying attention.
The odd thing is that this also happened in my Camry. In the Camry, there was even a sensation of the brake pedal sinking slightly. The sensation always vanished when I paid attention to it and like the HL, I could never reproduce it when I was trying to. In between the Camry and the HL, I owned a Buick Rendezvous for 8 years and it never happened to the Buick so I don't THINK it is anything I am doing.
My '02 HL does this occasionally when the A/C kicks on at a stop light--the idle bumps up a tad and the manifold vacuum rises slightly, which causes the brake pedal to sink a bit as the booster assist is higher for a given foot pressure. The higher idle also makes the car want urge forward more. Never noticed it the '08.
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'08 Highlander Base with goodies
'02 Highlander V6
'01 Honda Civic
'93 Camry LE V6 (departed)
Interesting. I'm pretty sure this has occurred when the A/C compressor is not enabled but I'm not absolutely sure. I'll have to see if the defrost is on the next time it happens.
The idle speed can also kick up with electrical loads, like when the radiator cooling fans turn on
Yeah, I thought of that one. I have not actually noticed the idle speed rise... it seems to compensate but not overcompensate. And of course in the colder weather we have here now, I'm not sure the radiator fan comes on in normal driving unless it is in response to the A/C. But I'll keep an eye on it.
What you describe sounds normal. We get accustomed to applying "just enough" pressure to the brake pedal to keep the car from rolling. Variables like increased idle and even accessories cycling on and off can override this. If all that is needed is a slight increase in pressure, you are most likely fine.
I may be "fine" but is disconcerting to find myself rolling towards the car in front of me. I also find it odd that in all the cars I have owned since I started driving in the very early 60s, my two Toyotas are the only ones that seem to do this. My Buick had the same sort of electronic throttle control that responded to loads and the A/C compressor and it never did it.
I guess it is time to change my driving habits and apply more pressure after I come to a stop, to prevent this. But since the vehicle has computer control of the braking system, I wonder why it doesn't do it for me so no change in braking habit is necessary.
pg, I'm with ya on the annoyance. My Toys are the only vehicles in 30 years that have done that. For my 02 HL, several years ago I drove with an OBDII scanner connected; the computer allows the in-drive idle to drop as low as 600 RPM and slow to come back up, and when the A/C kicks on it jumps to about 730, that appears to be when I notice the lurching most. Most of the time the idle goes no lower than 640 to 670 and cycling A/C or cooling fans goes mostly unnoticed.
I've mused that the throttle plate stop setting is maybe a tad off and the idle feedback loop is intentionally more sluggish than my Honda's/Chrysler's/Ford's/GM's of the past. I know Honda's especially have a pretty fast idle speed feedback loop; they have a special idle learn procedure so that the thing doesn't "hunt".
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'08 Highlander Base with goodies
'02 Highlander V6
'01 Honda Civic
'93 Camry LE V6 (departed)
Hmmm... I hadn't considered the possibility that the idle was lower as you came to a stop and then increased. I'll have to see if I can observe that. But it would certainly explain the creeping.
I may be "fine" but is disconcerting to find myself rolling towards the car in front of me. I also find it odd that in all the cars I have owned since I started driving in the very early 60s, my two Toyotas are the only ones that seem to do this. My Buick had the same sort of electronic throttle control that responded to loads and the A/C compressor and it never did it.
I guess it is time to change my driving habits and apply more pressure after I come to a stop, to prevent this. But since the vehicle has computer control of the braking system, I wonder why it doesn't do it for me so no change in braking habit is necessary.
Paul
Buicks have Godzilla brake boost. Toyotas do not. Not really rocket science (yes I am only poking fun). I have actually noticed a very similar thing in our Accord vs my GMC truck. Maybe it's a Japanese vs American car design thing.
Godzilla brakes? Not hardly! The biggest difference I found between the Rendezvous and the HL was the HL has WAY more sensitive brakes (which I seriously like). But that could also set up this condition if the boost changes.
I didn't say it had Godzilla brakes. I said it ran a lot of brake boost. Barely touching the pedal at a stop would hold it in place. Most American cars are like that. My GMC truck is that way. My Accord is very much like Toyota you describe. It's a difference, not a defect.
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