HI guys, a couple of weird things just happened as I was leaving a meet tonight. We got out of the restaurant and noticed my rear lights were on!!! No lights on in the front, just rear lights. So i start the car and start driving off, stay at the red light and start pushing the pedal and it goes but almost right away NO POWER, I am pushing the accelerator, am in DRIVE and am getting nothing, I am moving forward but barely, tried to go into TIP downshift but no power, so I m holding traffic doing myabe 15mph, go back into D then left go of the accelerator and try pushing again, then the car goes.... Drives normal, actually felt strong... 5 miles later, road is going down so I am coasting down about 40mph the normal speed on that street and it starts going up so I push the accelerator again to maintain speeed and nothing again! Scary no acceleration even though I am pushing on the fricking pedal!!!! Then after a few times of letting go and pushing again, power returns...
So I get home, turn off lights, turn the car off, lock the doors and walk away.. I turn around and guess what... The fricking rear lights are on again!!!!
UN real, unlocks the doors again, turn lights on and off... rear lights are still on! I start the car and turn it off... same... Finally I push on the brakes, same... I lock the doors again... rear lights stay on, then after 10 minutes turn off automatically!!!!

is this a fuel mgmgt issue? A limp mode? and are the rear brake light on a coincidence or some type of built in warning to let you know something is wrong??? but what?
This had happened to me once months ago and never had a problem after that night until today.... Real weird!

NO CEL, no codes on OBD II
I don't have a vag.com

You guys have any idea...
Don't know if it is a coincidence but earlier today I heard some buzzing noise for the engine compartment, not evey loud but heard it... Was afraid it was a turbo..

Thanks in advance.

 

Bad brake light switch is probably causing both problems. The brake light switch is causing the brake lights to stay on. Im also assuming you are drive by wire. On the drive by wire system the brake pedal being applied or in this case the ecm thinking its applied will override the throttle and cause the no acceleration. Replace the brake light switch and both problems should disappear.

 

Agreed with Dankhound as usual. The brake light switch can cause all kinds of s***.
Just becareful installing the new switch because its easy to break them.

 

Thought so. Had a similar exp. with my Saab. Brice, I saw you posted the same in audizine as well, where did you got the reply first?. Haven't checked ur thread again there.

 

Found someone, I think, whowill try to VAG my car and look at it later today... I got questions for more details,,, and suggestions like break switch, ecu problem and such

 

brake switch is like $30 so hope it is the problem
Not sure where it is though to change it.

 

BTW nocturnal, here is another answer i got on audizine, never heard of this issue...
"
In regards to the rear lights, it is the light switch that's causing the problem. The connectors are probably faulty and need to be replaced. I ran into the same scenario with my car....I woke up early one morning to find all my rear lights on, I immediately thought that someone was trying to steal my car so I ran out in my pajamas with a baseball bat ready to swing for the fences LOL. IF your car is still under warranty, take it to the dealer cuz it's covered, if not head to your local indy.[/align]"

Also I just drove 30 miles to an appointment and car did fine thougb I was worried the whole time it'd act up on I77 N!
Very spotty, not consistent

 

The brake light switch is a common known problem around the technician world. The manufacture that makes them was on crack or something when they designed them. They made several different types of switches which are different colors but they all suck. I've had to replace three switches one time just to fix the car because the ones on the shelf were already broken.
The switch is right above the brake pedal. There is a square side and a round side, you insert it and twist it until it locks. (DON'T TRY AND FORCE THE SWITCH BECAUSE IT WILL BREAK)

As for testing the switch, what isn't commonly known is how to use the data blocks to diagnose it. A lot of times the switch won't throw a fault code, to tell if its not working correctly you go to data block 2 in the brake electronics (VAG COM) and watch the detents activate in cascade.
While slowly pushing down the pedal the first detent should activate and then the second shortly after. If the second one activates before the first one the switch is bad, the same applies if both detents activates at the same time. Its easy to see once you have the vag com. Its also a commonly miss-diagnosed problem in dealerships.

 

Thank you, great help!
I am trying to meet with this person to VAG it. He works in a local shop and hopefully wil be able to help with the above diagnostic. he says he does not have switched in stock...
Do you recommend I just get one from the dealer, I assume they stock them... or on line form a place like ECSTuning?
BTW, does it make sense that it acted up last night and worked well just now, I drove over 40 miles wiht no issues.
I assumed that if the switch was bad it would create this problem consistently.

THANKS agian, very helpful guys.
I am sorry to bother you with this on a week-end. I just need to drive th ecar inlcuding tomorrow morning at 6:30AM and wanted to have an idea of what it was....

Brice

 

I would get the switch at the dealer, if its happening not consistently then the switch probably won't throw a fault code but its still probably bad.
Another thing to note, after installing the switch if the lights don't come on or stay on you can remove the switch and pull out the anvil and try again.