# Intermittent no throttle



## toddrs93 (Jan 5, 2011)

I am a tech for a shop that sees alot of VW cars. Two times in the last year we have had cars with this issue and chased them all over until we had to draw the line due to time and expense. 

Symptoms are that the car will start out fine and drive normal for a minute or two, sometimes less, sometimes more, then during normal driving the throttle response will just go dead. No matter what you do to the pedal, the car does not respond, its as if you are not touching the pedal at all and the car will coast to a stop. It will only come back to normal after coming to a dead stop. Then you can start out fine again. If you floor it right off the bat it will you get up to speed but eventually the throttle response will randomly die again.

On two different cars I have run through everything I can with a snap on Verus scanner that supports VW/Audi. I have monitored everything I possibly can. There are the two corresponding throttle signals that are redundant, and one is basically a back-up to the other. They should read opposite, for example one at 80% while the other is at 20%. Sometimes this happens and sometimes it does not. 

I have also run through all the online checks/tests and everything in ALLDATA. It all checks out fine as far as the pedal position sensor and throttle body actuator go. Continuity and resistance from both of those sensors to the ECU is also fine. 

By the way there are no codes in the ecu on either cars. 

At this point it seems replacing the pedal position sensor would seem logical, however I am hesitant to do so and incur that expense without something more decisive.

Given I have seen this twice, I would think others have as well. I just want to make sure there are no other issues maybe that are making it seem like a pedal position switch. 

Let me know, thanks


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## le0n (Jun 12, 2013)

do a full scan with vagcom/vcds.

not exactly sure what that snap-on tool does in terms of the later euro vehicles. anyone?

i'm wondering if it is the tcm is flaking.


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## rommeldawg (May 25, 2009)

i really dont like our verus for german cars. autologic and vcds are what we use on them. do as suggested and do a full scan on the car with vcds and post it in the 
ross-tech forum


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## toddrs93 (Jan 5, 2011)

unfortunately I do not have access to anything else. Snap on verus is suppossed to support alot of functions on vw/audi. And I can see what the throttle is doing, its just not giving me anything to go on.

The verus was like $10k, its a shame it doesnt go deeper into the ecu.


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## le0n (Jun 12, 2013)

^^ what's nice is that vcds is less than 300 and once people purchase and use it once or twice, it pretty much pays for itself.

even nicer, is when members in your area will run a scan for a free, a few bucks, or a six pack, etc.


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## rommeldawg (May 25, 2009)

i have been looking for more instances of this issue and am not able to find anything like it with out cel and codes involved. the reason i was suggesting vcds was that i feel it is better for vw/audi in many ways but that you could get some input from the programmers in their forum. if another comes in or you discover more info i am interested as to what you find. my guess would be wiring, had you done like a continuity check?


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## toddrs93 (Jan 5, 2011)

rommeldawg said:


> i have been looking for more instances of this issue and am not able to find anything like it with out cel and codes involved. the reason i was suggesting vcds was that i feel it is better for vw/audi in many ways but that you could get some input from the programmers in their forum. if another comes in or you discover more info i am interested as to what you find. my guess would be wiring, had you done like a continuity check?


yes I have done a continuity/ resistance check between the pedal position, throttle actuator, and ecm. 
I even checked each of the 6 wires at the pedal position sensor individually with a multimeter while driving to look for out of range variations or lost signal, etc.


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## LTJ (Feb 1, 2014)

*Similar Instances of Unresponsive Throttle in a 2013 VW Passat with 2.5L 5-cyl and 6-speed Auto*

In general, my wife and I are extremely pleased with our new 2013 VW Passat, with the 5-cylinder 2.5 litre engine and 6-speed automatic transmission. The balance of ride and handling in this stylish, roomy, German-designed sedan is among the best, most assured and most satisfying I have yet experienced, in nearly 40 years of daily driving. I believe that one can do far worse these days when executing a $20K automobile purchase. However, there have also been a few unfortunate instances of a possibly minor, but definitely annoying and so far unexplained, driving behavior with this car.

Although my experience with this problem may be less severe than the episodes already described here (thus far, coming to a complete stop has not been required in order to clear this condition) but I have experienced several transient and unexpected instances of greatly diminished throttle response in our 2013 VW Passat, during the initial months of ownership. At times, this occurs when trying to gently accelerate from a stop, and at other times it has occurred when going up a moderate highway incline at roughly 60 mph. My response has generally been to try and quickly give the gas pedal a good "kick" (well short of "flooring it") in hopes of restoring normal throttle behavior. However, such accelerator pedal engagement can briefly make throttle responsiveness even worse, and a couple of times this action has resulted in a sudden and undesired deceleration, even causing me to involuntarily tilt forward slightly in my seat, towards the steering wheel - as if I had just slammed-on the brakes and not the accelerator! (but I'm also 100% certain that pedal mix-up is not the true cause of this particular aspect).

Within the standards of this forum, comments and advice will be greatly appreciated!


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## SquattyD (Feb 2, 2011)

Also remember that when checking continuity, that really only tells you one thing, you also need to check to see if you are getting voltage as well, find out where the path comes from and where it goes first and second and see if you are losing voltage after a switch or sensor. It sounds like either a switch is going bad, possibly the pedal itself or something else, or even a path to ground does not have a good connection. I wish I had more electrical knowledge on VW, just in other things. That should at least get you pointed in a different direction to find the problem. A wiring diagram would show the path of electricity for you and what is connected in the circuit, hopefully you can get your hands on one.


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## Anile_eight (Sep 30, 2009)

I had an issue with intermittent throttle and after a couple time of that cycle my cruise would stop working. I replaced the brake light sensor and it seemed to fix the issue. Of course with the computer, it cuts off the throttle when you apply the brake at the same time for a certain period of time. It was a simple fix and there are plenty of DIY's out there for it.


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## toddrs93 (Jan 5, 2011)

highly unlikely cruise control is related to my issue.

UPDATE replaced the pedal position sensor/assembly and NO change


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## Geo (Nov 14, 2000)

toddrs93 said:


> highly unlikely cruise control is related to my issue.
> 
> UPDATE replaced the pedal position sensor/assembly and NO change




Anile_eight could be on to something though. He wasn't saying cruise control was the source of the problem, but was a system affected by his issue. The brake light switch malfunctioning could cut the throttle. Do you get any different results with traction control on vs off?

is your diagnostic software able to perform throttle body adaptation?


also, where are you located?


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## le0n (Jun 12, 2013)

toddrs93 said:


> highly unlikely cruise control is related to my issue.
> 
> UPDATE replaced the pedal position sensor/assembly and NO change


if you're trying to tackle this without vagcom, you're just going to be throwing parts at the problem. once you have purchased and replaced all of the "locigal" items, it may or may not work.



le0n said:


> ... *members in your area will run a scan for a free, a few bucks, or a six pack, etc.*


don't over think this. put out a message to find someone near you with the correct tool to diagnose the vehicle.

the worst that can happen is that you'd end up ordering a vagcom cable for yourself after seeing its capabilities.


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## stratclub (Feb 3, 2007)

Anile_eight said:


> I had an issue with intermittent throttle and after a couple time of that cycle my cruise would stop working. I replaced the brake light sensor and it seemed to fix the issue. *Of course with the computer, it cuts off the throttle when you apply the brake at the same time for a certain period of time. It was a simple fix and there are plenty of DIY's out there for it*.


 ^^^^^^^:thumbup:

If I was to throw any parts at it, I would replace the brake switch. There a 2 contacts in the switch, one for the ECU and one for the brakelights.

If the CC fails to set or disengages when the trottle operates funny, would pretty much point to the brake light switch.


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