Help - EPC / Traction Control / CEL / Limp Mode

A6 All/ S6 All
#1

Hey Everyone,

It’s been a while since I’ve posted (last post here about my CEL Saga ( http://audirevolution.net/forum/index.php?topic=3933.0 ). This time, I was driving the car around 40 MPH, and had the EPC/Traction Control/ CEL lights come on and the car went into limp mode. I had the car towed to the dealer and today was told it’s a MAF issue that caused a throttle body to get stuck open (At least, I think that’s what they said). Based on some cursory research online, it seems this may be a somewhat familiar set of symptoms that result in the same “fix one part, drive away, fix another part, drive away, repeat”, so I’m concerned it may not be just a MAF issue. Below is a link to a video so you can hear what’s happening. Any guidance here is appreciated! (still haven’t bought the VagCom…)

https://www.dropbox.com/s/7yfvhsy5qpgc3f3/Sequence%2001.mpeg?dl=0

So far I’ve had the following done from the first set of issues:
Entire manifold replaced
Checked for vacuum leaks and replaced a hose with a very slight crack
Carbon Cleaned (walnut blasted)
New spark plugs
New Coil Packs on cyl 5-10
New PCV (Crankcase Valve)
New Fuel Injectors on cyl 5-10

With the new issues they’re replacing:
MAF
Upper Control Link Bushings (perhaps unrelated, but noticed while doing the inspection),

#2

95% sure it’s the high pressure fuel pumps going out. Check out my post in the InfoDump thread. Can swap them out yourself, should be able to find the pumps for about $350 each, and you should replace both at the same time even if only one is bad.

Edit: just watched the video… wtf? does the exhaust really sound like that??

Having watched the video, now I’m only 50% sure on the HPFP’s being the problem… when mine went out, my car idled normal and sounded normal, I just got the “limp mode” and the same 3 warning lights as you, but the car drove OK as long as I took it easy on the throttle and kept it under 4k rpm.

#3

That sounded terrible! Not knowing much else it might be another terrible exhaust leak near the IM or maybe your cam tensioners are bad? Could be a myriad of things, but MAF doesn’t come to mind with that noise.

Hope you get it sorted soon!

#4

Ya the more I think about it, it doesn’t really seem like a HPFP issue like I originally suspected, sounds like something completely different. I honestly have no clue, I’ve never heard an exhaust sound like that. That’s why I was asking if the exhaust really does sound like that, or if the camera microphone was just distorting the sound. Sounded almost exactly like this:

https://www.youtube.com/watch?v=t8CJFoAyn6U

#5

Ok do you get a blinking CEL or just the other lights and they are steady.

that noise sounds like something is broken in the exhaust and sounds very wrong. The car is chugging so there is something wrong. you can pull both the MAF wires and see if it gets better but I would have to guess that is not going to help.

With this kind of thing you really would be worlds ahead if you had a vag com. That will really help you help yourself and with the dealer doing a part here and a part there. Its best you get a vag com or at the very least have autozone or your local parts store get you some infomation on exactly what codes the car has.

#6

@c.scott - Yep. It actually sounds like that (and that video you shared…). Hence my concern that the “MAF” isn’t the driving force behind the problem… I parked it overnight and had it towed to the dealer in the morning. In the morning it wouldn’t even turn over.

@Justincredible - CEL was solid. I’m fortunately/unfortunately becoming fairly friendly with the dealer’s service team so I’ll see if I can get the codes from them.

They were supposed to have the MAF swapped today, but no word yet. Will update soon.

#7

please let us know. The codes will tell us alot about whats going on.

#8

Don’t know if this will help you, but I had a similar situation on my '09 (at 36k miles last week). Started it in the morning and the dash lit up will all of the lights (ABS, Traction ESC, check engine, etc.). Lights went out after 1/2 mile and car ran fine. Got on the highway and no cruise control. Pulled over, shut it off, and after a restart, everything worked normally.

Took it to lunch that day and same problem. Stopped for gas, and when I pulled out of the gas station it felt like a 4 cyl. Wouldn’t go over 40 mph. Mad an appt. to have the dealer check it that afternoon. They scanned it and told me that the ECU was shot, and it needed a battery ($2500). I told them to go ahead and fix it. I’ve now been driving a loaner for over a week.

Got an email from the dealer today telling me that I may be able to get my car back tonight. They did not put an ECU in it. New battery, Battery cable, loose ground in engine bay, and dirty connectors at the throttle body.

Mine sounded similar to yours, except it threw a P2101 code for the throttle. You may be chasing a wiring issue.

Good luck, and I will let you know what mine was for sure when I get it back.

#9

It turns out that mine was a wiring issue. Got it back this morning and it works great again. $631 worth of diagnosis and fiddling seems to have solved the problem.

#10

WOW really. What wires were damaged and did they need to splice in anything or just repair the section. Maybe there is a chance that the wire harness on some year S6s was brittle in the same spot

#11

From their description it appears that they cleaned the electrical connections and the throttle bodies, then performed a reset/adaptation on the throttles.

#12

HMMM. the connections are connected all the time so how they would get dirty dosent make much sense. The relearn of the throttle bodys makes sense tho thats a common issue