No throttle when brake pedal is pressed.

[static667]

This issue just came up. I was on my way to work and went to do my usual heel-toe down shift and got nothing. I messed with the idea for a few minutes and came to the conclusion that when the brake pedal is pressed, you get no throttle response. I put one foot on the brake and floored the gas. Nothing. Take foot off of the brake, tap pedal, revs go up like they should.
When I did my oils filter housing gasket yesterday, I had the battery disconnected for the better part of the afternoon. Could this have something to do with it? Did the lack power reset something? WTF?

Please help, I want my heel-toe downshifts back. :(



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[HokieZHP]

It's a safety thing. The throttle is supposed to shut off if the brake is applied. Sort of a runaway car prevention thing


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[LivesNearCostco]

Yes, on a new Toyota! But my car--and apparently static's car before the OFHG replacement--I can press the brake and still rev the engine.

Static: Disconnecting the battery for a few hours might reset the adaptive whatchamacallits, which can affect throttle response, but I haven't heard of it adding some new brake-throttle safety interlock. Unless the BMW dealer sneaked into your garage and reflashed your DME while you were taking a bathroom break.

[llll1l1ll]

Mine seems to rev just fine for heel-toe - at least, as far as I can tell.

[static667]

Never had the issue before. It really puts a damper on my driving.



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[Newjack]

So does mine. I can hit the brakes and rev the nuts off my motor if I wanted. That's a really bizarre problem Static, I don't know what it could be.

[HokieZHP]

Are you talking about when it's in gear on in neutral? When I'm cruising down the highway on throttle and press the brake my throttle cuts but in neutral i can rev it with my foot on the brake.

I think I misunderstood your question

[Newjack]

What do you mean by "When I'm cruising down the highway on throttle and press the brake my throttle cuts" Are you saying that if your cruising and brake while in gear giving it more gas while braking does nothing to increase revs?

I never brake while in gear, so I have never tried to do this. I have also never attempted a burn out (as badly as I want to I'm to paranoid I'll break something)

[HokieZHP]

No I mean if I have my foot on the throttle driving and then press the brake, it will cut the throttle as a safety switch for runaway cars or if the throttle gets jammed. In other words, the brake will always overpower the throttle because when it is pressed, the throttle cuts out completely.

I did it to see what would happen. I'm pretty sure all modern cars have this feature. Both of my parent's audi's do and my brother's subie.

[Hornung418]

...Chris, I'm not sure what you're talking about, but if you're in gear and doing that of course you're not going to get any response, as the car is slowing down.

What Kyle is experiencing is completely different. He's braking in gear, depressing the clutch with his foot still on the brake then blipping the throttle and downshifting. The clutch is depressed so technically it's in Neutral, and the foot is still on the brake, this is not a safety precaution. Something has changed.

Unfortunately, I'm not sure how to respond, Kyle :( Never had this problem.

[LivesNearCostco]

I'm gonna have to try this again. I know if the clutch pedal is in, I can press the brake and rev the engine with the gas pedal at the same time. Not sure if it works when the clutch pedal is up. AFAIK the DME has no idea what gear an E46 MT is in, except maybe reverse.

Chris: Are your parents' Audis and brother's subies manual or automatic transmission?

[RITmusic2k]

Is there a possibility that this is true on cars with automatic transmission? It's definitely possible (assuming the car is functioning normally) to apply throttle while braking in a manual.

[HokieZHP]

Alright I give up trying to explain. You guys can try it next time you go driving. Go at a steady speed and then get on the throttle then just after start braking (while still on the throttle) and see what happens... It doesn't cut immediately but does after a couple seconds


Sorry to drag this thread off topic...

[ryankokesh]

I gotta try this...

[wsmeyer]

No safety feature like that on my 2006 Manual. My parents have a 2010 Toyota Avalon and I was wondering what the safety switch felt like but to my surprise, it doesn't have it either.

Car and Driver did some testing on the effects of full throttle on braking:

http://www.caranddriver.com/features/how-to-deal-with-unintended-acceleration

William.

[static667]

I figured out the issue. In the final re-assemblies of the air box, I forgot to hook up the MAF sensor. :facepalm I plugged it back in and problem solved. Go me!


No I mean if I have my foot on the throttle driving and then press the brake, it will cut the throttle as a safety switch for runaway cars or if the throttle gets jammed. In other words, the brake will always overpower the throttle because when it is pressed, the throttle cuts out completely.

I did it to see what would happen. I'm pretty sure all modern cars have this feature. Both of my parent's audi's do and my brother's subie.

I know what you mean here, Chris. If you ride your break for a few seconds, the car cuts back on the power automatically. Go out and try this one yourself, kids!

[LivesNearCostco]

Welcome to the MAFia!

[llll1l1ll]

Welcome to the MAFia!

Haha!

[az3579]

I figured out the issue. In the final re-assemblies of the air box, I forgot to hook up the MAF sensor. :facepalm I plugged it back in and problem solved. Go me!



You should have gotten an SES light for that...

[Ryans323i]

This is one for the books. I'm sure this will happen to someone in the future. Glad you found the solution, it's very concerning to have something change after a DIY.

[static667]

My SES light is already on...



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[az3579]

My SES light is already on...



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Ah, explains it.
Nevermind then.


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[terraphantm]

My ZHP only did this when I had my MAF unplugged.

edit: looks like he already figured it out. Never mind.