# Anyone else having accelerator problems???



## GtiGuy1 (Mar 28, 1999)

Car is a V-8 and about two weeks after purchase, the car developed a problem whereby the accelerator will quit for about two to three seconds. This only happens when I slow to a near stop, not a full stop and then pull away. This is not to be confused with the normal downshifting hesitation which is short in duration. This happens regularly, but I have had several encounters when I was crossing a busy street, rolled into it, punched the gas and wound up sitting in the middle of oncoming traffic. Nice! The dealer says everything is fine on the computer and that this is a safety feature that VW built into the car to stop wheel spin, but it happens with the ESP deactivated as well. Unfortunately, it doesn't happen on command so the dealer hasn't been able to experience it. VW is going to play ostrich with me. You would have thought they would have learned a lesson with the Audi 5000. What does it take to get people to respond.


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## mdjak (Aug 13, 2003)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

when my BMW 330xi, 2001, was new, it didn't just have acceleration hesitation, it would stall-out in the midle of intersections. Of course it either never did it for the dealer or they wouldn't admit it. They updated the engine management system a number of times, sometimes making it worse. Finally, they gave me a loaner, the service manager took the car for a week and said he would not give it back to me until it was fixed. It was a lease, so I was glad to put miles on a loaner for a while. They finally fixed it and it never happened again.
One suggestion: Use the tiptronic mode exclusively at least for a while. This way, you can see if it is transmission downshift hesitation or an engine "acceleration" problem. Also, I went so far as to hold, or have my son hold, a video camera on the dashboard so I would have evidence of it stalling out. I know these are not necessarily solutions to get them to recognize it, and they may be a pain in the you know what, but it might help. also, whenever I've had a problem that the dealer claims they can't duplicate, I insist that either the service manager or one of the techs come for a ride with me. They usually like getting out for a while. I also had a very annoying creaking sound from the back of my BMW that they never acknowledged hearing. I took a tech for a ride and he heard it and fixed it, finally, after a year of feeling like I was driving my father's Checker Cab!
Good luck.


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## Uwe (Jan 16, 2000)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

As you're probably aware, the Touareg (like most modern cars) has a "drive-by-wire" throttle. In other words, there's no mechanical connection between the accelerator pedal and the throttle. The accelerator pedal is nothing more than a sensor, and the throttle is motorized, actuated by the Engine Control Module. 
Now the program in the Engine Control Module has some logic in it that, under certain cirucmstances says: No throttle of the the brakes are applied. This logic was implemented (at least in part) due to the Audi 5000 "unintended acceleration" nonsense!
The first thing to check is (and I don't mean to insult you with this) is that you don't have your foot on the brake!








Assuming there's no possibility that you've got your foot on the brake, my money is on a defective (sticky) or misadjusted switch on the brakes. I'm not 100% sure which switch it is (the brake pedal position switch or the brake pressure switch). However, the ECU "sees" the position of the switch and won't open the throttle.
I had a customer with a 2001 Audi A4 2.8 Tiptronic that had this problem for 2 years. Dealer could never reproduce it or find it. The guy then bought a VAG-COM and started logging data from his ECU. It didn't take him long at all to get data showing that there were times when he on throttle pedal but the throttle wasn't opening. What took a little longer was to figure out why -- the ECU incorrectly thought he was still on the brakes! 
FWIW, the dealers have a terrible time with stuff like this because their own (very expnsive) scan-tools can't log data or present it in a graphical format, and that makes it very hard for them to catch "glitches" like this.
-Uwe-



_Modified by Uwe at 9:50 AM 10-19-2003_


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## GtiGuy1 (Mar 28, 1999)

Thanks for the reply. I've probably been quilty of driving with my left foot on the brake, but not at every occurance. I'll mention this to my dealer. Tks.


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## ButteBeautie (Aug 16, 2003)

*Re: Anyone else having accelerator problems??? (Uwe)*

uwe ...
Good description of "throttle-by-wire" ... and "engine/tranny/brakes logic '' ... I buy it all.
Reason for my response this time (I have written at length about this issue ... even starting a separate Topic about 8 weeks ago) is: so I can ASSURE others (and you) that this "heart-sinking event" occurs with NO FOOT / HAND / HEAD / COFFE CUP / DOG / CAT / SNAKE ... ANY WHERE NEAR THE BRAKE PEDAL! (I'm a "one-foot driver" ... and I don't "heel-toe" my Touareg!)
I also buy the "faulty brake sensor" thing ... I don't buy ANY VW Dealer's ability to analyse ... or FIX it. If there was one/any, then VW (and Audi) would (as one recent member described) NOT be in the "Ostrich Mode!"
Having said that, I had a "VW Car Care" telephone guy agree with my LOGIC that it had to be one of four things:
1. No fuel
2. No air
3. No "go" (software)
4. No GOOD! (a SERIOUS SAFETY ISSUE)
Guess that's about all the progress one can expect at this juncture.
On the legal side: I'm PRINTING-OFF EVERY INPUT TO THIS (and other) Forum that deals with this subject. The "paper" is in the safe that my wife is supposed to open and share with our attorney if/when I get turned into Strawberry Jam by a very large truck whilst attempting a left turn through on-coming traffic. She will be rich beyond her wildest dreams ... BUT, I know will miss the "materials, fit & finish" we love so much in this otherwise SUPER-performing car!
The saga goes on ....


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## GtiGuy1 (Mar 28, 1999)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

There is another post in this forum from a 63 yr old man in Denver who is having the same problem.


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## Torags (Aug 18, 2003)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

This is why you need electronic adjustment:
"A throttle by-wire system replaces the cable connecting the gas pedal and throttle valve(s) with an electrical connection. The throttle is electronically controlled for more efficient operation. In addition, electronic throttle units enhance safety systems such as a traction control system (TCS) or electronic stability program (ESP). 
A steer by-wire system replaces the steering column with control units linked by a fault-tolerant network. The driver's steering controller is connected through the network to motors that are connected to the steering rack or individual corners. Steer by-wire systems enhance safety, increase fuel economy, provide varying levels of “road feel”, and allow car designers more flexibility. 
A brake-by wire system uses electrical connections to connect the four braking “corners” to the pedal and to each other. This system provides better control of pedal stiffness, traction control, vehicle stability, and brake force distribution."


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## ButteBeautie (Aug 16, 2003)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

gtiguy1:
thanks ... I could not find the post you are refering to ... would you tell me which thread you found it in? ( ... 63 year old guy in Denver ... ") Maybe I saw it BUT, defiantely want to catch ALL the "high-altitude examples" ... that is where I had the greatest occurance.
Thanks,



_Modified by ButteBeautie at 8:21 PM 10-20-2003_


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## nbakker (Jun 25, 2003)

http://forums.vwvortex.com/zerothread?id=1016554


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## Uwe (Jan 16, 2000)

*Re: Anyone else having accelerator problems??? (ButteBeautie)*

Butte,
Based on the additional descriptions you've posted, I'll give long odds that my theory is the correct one. Your Engine Control Module won't open the throttle because it thinks the brakes are still on. 
What you want is a log of measuring block 008 and 062.
008 Field 1 shows whether the ECU thinks the brakes are applied or not. 
http://www.ross-tech.com/vag-c....html
062 shows both the throttle position and the accelerator pedal position in %.
http://www.ross-tech.com/vag-c....html
What you're looking for there is a condition where the accelerator pedal is pressed but the throttle isn't opening. When you find it, see if the ECU thought the brakes were still applied. There's your culprit.
Feel free to print this message (and the pages in the links above) and take it to the dealer -- it might enlighten them. 
-Uwe-
PS: [Shameless Plug]
If you have a laptop, you could get a VAG-COM system, record the data youself and put it under their noses.


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## ButteBeautie (Aug 16, 2003)

*Re: Anyone else having accelerator problems??? (Uwe)*

Uwe,
Someone else (sciencegeek) JUST put me [back] on to this thread ... thanks for technical information ... first time I've heard THIS [possible] cause ... WILL print-off an carry to the Dealer (when we have our "show-down" later this spring ... as, I can't get there from here right now ... seriously!)
Hope this IS the answer ... if so, it will also in you the gratitude of MANY VW AND AUDI owners ... as well as the "Nobel Saftey Prize."
Thanks again,

















_Modified by ButteBeautie at 9:06 AM 2-7-2004_


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## mr.vw (Oct 9, 2003)

*Re: Anyone else having accelerator problems??? (Uwe)*

Uwe..could just be the throttle adaption is off/incorrect...
Might just need to be reset or re adapted


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## darylhuff (Dec 1, 2003)

*Re: Anyone else having accelerator problems??? (mr.vw)*


_Quote, originally posted by *mr.vw* »_Uwe..could just be the throttle adaption is off/incorrect...
Might just need to be reset or re adapted

I'll ask the same question as I have on a number of other threads on the same topic, does anyone have any *facts* on this supposed "adaptive" throttle in the Touareg? All I've seen is supposition and conjecture. There is no VW documentation or marketing material that suggests the Touareg has a throttle system that adapts over time to a drivers habits. In order for either of the reset proceedures floating around in this forum to work, would require that there actually be an adaptive throttle system.
http://forums.vwvortex.com/zerothread?id=1221786


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## mr.vw (Oct 9, 2003)

*Re: Anyone else having accelerator problems??? (darylhuff)*

its not the throttle that adapts...it's the transmission...
I was referring to the actual throttle position...it has sensors that guage how "open" or "closed" it is... it gets its signal from the sensors in the pedal....if you've had a loss of power(dead battery), you'll probally need to recalibrate/recode the TPS sensor...has to be done with the 5052 scan tool


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## jlturpin (Oct 22, 2003)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

VWOA bought my first treg back VIN 33xx, bought an X5, sold it and then bought another Treg VIN 498XX. It had terrible hessitation. The new one has only hessitated after switching drivers for a few days. Nearly 3k on it in the first month. We love it. The first treg would stop responding for long periods of time and would not accellerate and loose speed while driving down the road. Had it a month, put 600 miles on it, mostly between my home and the dealer and parked it in my garage for less than a week.


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## toddd (Apr 11, 2004)

*Re:throttle hesitation / brake interaction*

In trying to find a solution to my '04 Touareg's throttle hesitation problem, I found this forum. After reading a post stating that the engine control computer would not allow the engine to accelerate if it sensed the brake pedal was being depressed I tried it out-- Bingo!
Sometimes I -could- apply engine power with my left foot on the brake, other times I could not. Sometimes the ECC would slow the engine a few seconds after I started pressing the brake pedal. Sometimes the engine would remain at idle even -after I removed my foot from the brake-. WaaLa!! 'throttle hesitation' explained. It is caused by poor response to a brake pedal sensor. The response is inconsistant & often slow.
I was able to recreate all degrees of 'throttle hesitation' at will!
Please try this out & post your results. Just lightly depress the brake while pressing the throttle. Then release the brake. What happens?


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## Silver Fox (Feb 10, 2004)

*Re: Re:throttle hesitation / brake interaction (toddd)*

Why would you or anyone want to drive with 2 feet on the pedals? You can't double clutch with the TREG. Seems dangerous.
What am I missing?


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## spockcat (Jun 5, 2003)

*Re: Re:throttle hesitation / brake interaction (Silver Fox)*


_Quote, originally posted by *Silver Fox* »_Why would you or anyone want to drive with 2 feet on the pedals? You can't double clutch with the TREG. Seems dangerous.
What am I missing?









What you are missing is that if the brake switch is slow to react that it will "think" you are still on the brake when in reality you have released the brake. In "thinking" that you are still on the brake, the ECU will not allow the throttle to open.
This is what Uwe Ross suggested might be happening and he had a customer prove it was happening with his A4.


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## cybulman (Dec 18, 2003)

*Re: Re:throttle hesitation / brake interaction (spockcat)*

This may be a real stupid suggestion, but could double tapping the accelerator pedal help in any way...like a racing car driver ya know?..or will it confuse the bird on the wire even more???
Cy


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## toddd (Apr 11, 2004)

*Re: Re:throttle hesitation / brake interaction (spockcat)*


_Quote, originally posted by *spockcat* »_
What you are missing is that if the brake switch is slow to react that it will "think" you are still on the brake when in reality you have released the brake. In "thinking" that you are still on the brake, the ECU will not allow the throttle to open.
This is what Uwe Ross suggested might be happening and he had a customer prove it was happening with his A4.


Exactly.
In addition, I -do- actually have feet on both pedals sometimes when I need to go real, real slow. Like when I'm backing into my garage, right up against the file cabinets on the passenger side, I want to be ready to apply the brakes in a instant if I've misjudged.
Also (although I haven't 'tregged' off road yet) I've been in tight spots with other vehicles where I needed to go very slowly over something, but had to guard against lurching forward once I was on top of it.
I believe this is a big reason many people prefer automatics when off-roading. I certainly do.

Todd


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## isolani (Jan 23, 2004)

*Re: Re:throttle hesitation / brake interaction (toddd)*

Ok, I suspect this is the solution to my hesitation as well, but what's the solution?
I find that if I flip my left foot under the brake pedal and pull it up, the car will go sooner. But this is hardly an ideal fix.
Has anyone managed to convince VW to replace any parts to fix this? Is it just the brake light switch? Or is it more complex, maybe the master cylinder or a spring or something?
Isolani


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## aircooled (Jul 30, 2003)

*Re: Re:throttle hesitation / brake interaction (toddd)*


_Quote, originally posted by *toddd* »_
Also (although I haven't 'tregged' off road yet) I've been in tight spots with other vehicles where I needed to go very slowly over something, but had to guard against lurching forward once I was on top of it.
I believe this is a big reason many people prefer automatics when off-roading. I certainly do.


And this is exactly my problem with it off road. No being able to closely articulate the throttle response when traversing obstacles will get me in trouble. Perhaps a switch can be installed in line of the brake pedal sensor to stop this behavior off road. I say off road mostly because you would probably lose your brake lights in the process.


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## toddd (Apr 11, 2004)

*Re: Re:throttle hesitation / brake interaction (aircooled)*

I'm the guy that proved (to himself) that the throttle hesitation was caused by incorrect or slow response of the ECU to a brake sensor.
I took the Touareg to my dealer a few days later to demonstrate the problem to the service guy, have him agree with me & then the service department happily fix it. Sure. Wouldn't ya know-- I -couldn't- get it to happen! Only by applying a lot of throttle (& a lot of brake) could I get the ECU to respond.
Sooooo.. I came home & investigated what I imagined to be the culprit- the brake pedal switch. I was thinking like you that if I could simply disconnect something, the ECU wouldn't even know the brakes had been applied. The pedal sensor turns out to have 2 sets of contacts, one normally open, for the brake lights & one normally closed. The normally closed set senses brake actuation to allow the transmission to be taken out of Park, & maybe also to disengage the cruise control if you step on the brake. But as far as I could tell, neither has any effect on the ECU. 
With this normally closed switch open (signalling brake application) I could drive completely normally with no change in the 'throttle hesitation' characteristic-- I could still invoke it, but it didn't happen all the the time like I expected. I'll play with it some more next weekend, but I don't think the signal we want is coming from this switch.
So does anybody out there know where else there might be a brake sensor? Maybe on a brake line somewhere?

I took the Touareg off road yesterday and you're right about lack of good throttle articulation. The first 3/8" or so of travel produces nothing. Everything seems to happen in the next 3/4". The remainder of travel pretty much only effects downshifting. I think I can get used to it though. In low range, it seems to be less of an issue because a big change in engine speed doesn't cause as large a change in vehicle speed. 
The air suspension was a delight. I was able to travel much much faster over rough roads with more comfort than in my last SUV (a 2000 Durango). And I wasn't pushing it. 
Over really rough stuff we could hear the suspension 'top out' (when a wheel tries to go down but hits it travel limit) with clunks that didn't fit the other aspects of the car (have to ask the dealer about that), but overall I was thrilled with the car. Plenty of power too!!

Todd


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## SLCgateway (Mar 19, 2004)

*Re: Re:throttle hesitation / brake interaction (toddd)*

I have only 500 miles on my V8 and have had this happen twice. Wasn't sure if it was me or the Treg. Now I know that the problem is not this "65 year old man in Salt Lake City"! But after reading thru all the posts I still haven't seen any post of a dealers solution/fix. Are all you guys just living with it ... and potentially dying from it when we get creamed at some intersection !


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## sciencegeek (Oct 26, 2003)

*Re: Re:throttle hesitation / brake interaction (SLCgateway)*

plausible deniability. the preferred WMD in the dealer's arsenal for large-scale neutralization of customer complaints.


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## jonnyfin (Jul 2, 2004)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

I'm glad I found you guys! I thought it was just me this was happening to;
Got just under 15k on my V6 and this has happened at least twice. Usually i'm in tip 1st and will gun it from a full stop to break into traffic.....I get an initial push from the car and then, for what seems like forever (especially with a semi bearing down on you) I am absolutely not moving with accelerator depressed fully; no, the brake pedal is not depressed i'm a one foot driver.
Anyways, i love the car but i have no confidence in trying this kind of maneuver again... 
on a side note i had it in for 15k service yesterday and they fixed 6 recalled items; hopefully this was one of them!


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## TREGinginCO (Jan 4, 2004)

*Re: Anyone else having accelerator problems??? (jonnyfin)*

Not to hijack the thread... but why were you having a 15k service?


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## jonnyfin (Jul 2, 2004)

*Re: Anyone else having accelerator problems??? (TREGinginCO)*

It was actually the 10k service, only i forgot @ 10k and was doing it @ 15k... silly, all this maintenance was included with the lease
oil change..etc.


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## frank_kuchta (Jul 28, 2004)

*Re: Anyone else having accelerator problems??? (TREGinginCO)*

I have the same exact problem and reported the issue on several occasion to the VW service dept. They acted as though they had never received any complaints or reports of this problem. I know that's BS from reading all of this. If anyone has any update/legal complaint.... I'm there!


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## spinnetti (Feb 18, 2000)

*Re: Anyone else having accelerator problems??? (GtiGuy1)*

I have it on my v6.
Took it to two different dealers who both claim there is no problem, yet when I left both dealers, it did it right away as I tried to drive away. I called VW who was of course worthless.
Not sure how much hassle its worth to get them to fix it.
I am going to take a video of it doing it (on mine the rpm hop up and down as it sits there), and send it to the clowns at VW to see if I can get some action.


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## spinnetti (Feb 18, 2000)

*Re: Re:throttle hesitation / brake interaction (cybulman)*


_Quote, originally posted by *cybulman* »_This may be a real stupid suggestion, but could double tapping the accelerator pedal help in any way...like a racing car driver ya know?..or will it confuse the bird on the wire even more???
Cy

Funny you should mention that - I tried that very thing, also tried tapping the brake pedal and any number of things, all to no avail.
This really irritates me! (glad my race car is not drive by wire!!)... ON a related note, I test drove a bmw which had the same goofy problem.


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## spockcat (Jun 5, 2003)

*Re: Re:throttle hesitation / brake interaction (spinnetti)*

Have you had your transmission reflashed yet?


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## pvjq (Sep 21, 2003)

*Re: Re:throttle hesitation / brake interaction (spockcat)*

I have experianced the same problem...only twice in 9 months (3400 miles). I am having my transmission flashed this monday in hopes that it will correct the problem, but it happens so sporadically that I guess i won't know for sure unless it never happens again


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## spinnetti (Feb 18, 2000)

*Re: Re:throttle hesitation / brake interaction (spockcat)*


_Quote, originally posted by *spockcat* »_Have you had your transmission reflashed yet?

Yep, and after lots of experimenting, it has nothing to do with the trans... this is an ecu issue. They flashed my trans, but I never had any problems with shift points or anything anyway, so I couldn't tell any difference.


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## spinnetti (Feb 18, 2000)

*Re: Re:throttle hesitation / brake interaction (pvjq)*

Mine started out every once in a great while, and now its about 1 in 3 starts..


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