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Discussion Starter #1
I have a 2012 sx4 and it occasionally accelerates when i am breaking. I cannot stop the car by brake when this occurs. As i apply brake the engine accelerates and my only choice is to put in neutral to stop braking heavier will not stop the motion. this is concerning for it occurs at a stop sign or a red light. if i do not get it in to neutral quickly enough i could hit the car stopped in front of me or a pedestrian crossing the street. my daughter just got her license and my wife is not the best driver. while this happens rarely the suzuki service center cannot diagnose or re-create this scenario ... any others having this trouble or maybe suggestions?
 

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ENgine, type? WHere do you live?
I understand this is an automatic transmission.
A full throttle condition lowers vacuum hence power brake is inefficient.
Please confirm nothing on the floor (mats) would link the movement of the brake pedal to the throttle pedal..
Throttle is electronic...is the check engine light coming ON ?
 

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Have you totally discounted the possibility that your foot is covering both accelerator and brake occasionally?
 

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Discussion Starter #5
don't know enough to tell you engine type. theres nothing to make a link between the two petals. i would not say it goes full throttle but the harder i press on the brake the harder to hold it back. always happens within the 1st 5 minutes of travel or the 1st 1/2 dozen times i use the brake .. never has happened later on. i live in new jersey ... i would say no more than once a month, this is quite strange
 

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...... i live in new jersey ......
OK....details are important..now I know you have a gasoline 2 litres engine....in other countries, you can have diesel, 1,6 litres gas engines. etc...., which can behave differently; just knowing someone has "a car" is meaningless.
Again, what you experience is quite strange. However now we know it is occasional, a rather rare event...but anyway, being unexpected, it is a danger, I agree.
Just a few thoughts...THe throttle is electrically operated. Pressing the brake turns the brake lights ON.....is there a link ?....Chaffed wires?
 

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Discussion Starter #7
sorry LMP ... i am not mechanically inclined ... explained all this to the mechanics who are suzuki certified who could not help ...
 

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If they do not see it on their scanner, they will tell nothing has happened.
YOu will have to dig into this with a "private investigator", some mechanics buff who will like to find something and does not count his time....
 

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Discussion Starter #9
i get that ... was thinking it may be something others were experiencing to validate my situation, this is going to be a rough one i am more concerned about wife and daughter, i am on top of it when i drive they drive occasionally and may not respond as they should.
 

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I would still start by trying to remember what shoes you were wearing at the time. Has it actually happened to other members of the family?

Occasionally I can get a bit of a rev up while braking to change out of Park. It has always been a wider pair of walking shoes catching the edge of the accelerator pedal.
Once under way it never happens, I must move my foot differently from 1 pedal to the other..
 

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also how fast do you drive? i occasionally experienced the "feeling" of acceleration when distracted and going very fast while everyone else is slowing down. Then realizing that I need to slow down and hitting the brakes but not all way. I would say this happened a few times in the first few years of driving and with more experience I avoid this kind of situation now.
 

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Discussion Starter #12
Only occurs when i first start out .... 1st few corners or stop signs ... 25, 30mph at most .. never happens when car is warmed up ....
 

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OK..the car is about 4 year old now. WHen did it begin behaving like that ? Is it possible this happened after some kind of work , maintenance, oil change, replacement of some component....
 

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Discussion Starter #14
don't think so ... car has been trouble free except for this ... not sure when i first noticed it but it has been a few years at least. only occurs once or twice a month. suzuki service unable to do anything ... advised wife and daughter to keep hand on stick while breaking until car warms up to throw into neutral. no matter how hard you apply break you can't stop it it doesn't go fast but you will rear end the car in front of you or hit the person your slowing down for who is crossing the street.
 

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Powering the engine requires 2 things : air, fuel.
Air is taken from the throttle valve, electrically driven on this vehicle.
Fuel is fed according to the air flow, as measured by the MAF(mass air flow) sensor
Power brake requires 2 things: vacuum from intake manifold and atmospheric air.

When more air is fed to the intake manifold, vacuum is compromised, reducing power brake assist ….but it seems this happens as a freak event when depressing the brake pedal…..(while normally, throttle is closed – no foot on the throttle – when one applies brakes )
Power brake assist result from the fact that depressing the brake pedal opens atmospheric air to one side of the power brake diaphragm (while at rest both sides are at vacuum), while the other side is at intake manifold vacuum (negative pressure, relative) .
Ahh..just found that, real good: https://www.youtube.com/watch?v=LThrL8Jjsgc

There is also something special when engine is cold: IAV…idle air valve. This valve increases engine RPM (more air, more fuel) until engine is warmed up…..once warmed up, IAV resets to slow idle….

Soooo..trying to figure out some rationale, I’d inspect MAF sensor (clean?) and IAV…even if it is just to opt them out of the problem. I do not know why they would have gone awry, but as Sherlock Holmes said, supposedly, once you have eliminated all that is impossible, what is left is the solution…..
 
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