# Multiple Knock Sensor issues



## 07 2.5L-emon Wolf (Mar 25, 2008)

I have a 2007 2.5L Jetta Wolf manual. I have been in dealer service 5 times in less than 90 days spanning 9,500 - 10,100 miles for the same issue: Knock Sensor(s) fault code and then solid yellow CEL. Both knock sensors have been cleaned, retorqued, reinstalled or replaced new over these last 5 episodes. Every 200-300 miles after I leave the dealership the problem comes back. Here is what happens: car performs normally (not even an odd sound) until right at 3000 rpm, then the needle and throttle shoot down to zero while my foot is pushing the gas pedal on the floor. The car doesn't stall, but it forces me to keep shifting before I top out at a whopping 3k! Gas pedal is nonresponsive at 3000 rpm, no throttle response. 
What gives? I see a lot of problems with turbos, but this is the 2.5. Incidentally I see a lot of problems with the Wolfs...this must be a coincidence, right? What is different other than the badge, seat warmers and sunroof package? They must not take the time to separate parts for the Wolfs and regular 2.5s, ...right? I feel like I am on totally hidden video with this experience. Now the dealer and the VW Customer Care people tell me they are at the mercy of VW Tech Line to instruct the work. Huh? Can't they do investigative old fashioned mechanic work anymore instead of plugging in a machine?
I'm new to the forum, but a born and bred VW/Audi driver. I was floored to see there are 971 search results when I searched "knock sensor" issues so I gave up and posted this. I must have been lucky to have avoided any significant redundant problems with any of my past 7 VWs and Audis in the last 11 years:
1997 Jetta GL
1999 NB GLS
2000 NB GLX
2002 A4 1.8
2005 A4 Cabriolet
2005 NB GLS
and this POS 2007 Jetta 2.5L-emon
Any ideas? THANKS!


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## Audi4u (Jun 29, 2002)

*Re: Multiple Knock Sensor issues (07 2.5L-emon Wolf)*

Maybe it's not the sensor, could be the engine.
do you own a vag-com cable?


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## gonyofam3 (Oct 2, 2007)

*Re: Multiple Knock Sensor issues (07 2.5L-emon Wolf)*

I would check your states lemon law.


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## KampfGTI (Mar 28, 2007)

ecu is definitely goin into limp mode....it maybe the wiring b/t the knock sensors and the ecu or the ecu itself


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## 07 2.5L-emon Wolf (Mar 25, 2008)

*Re: Multiple Knock Sensor issues (Audi4u)*

Audi4u:
Nope, I don't have a VAG-COM becuase I don't do any mechanic work myself. I never keep my cars long enough. I like(ed) getting new VW's or Audi's...but that is all over now. Car was towed to the dealer 8 days ago for 5th episode of same knock sensor fault code/CEL, etc. They are out of options with VW Tech Line so they told me a "regional mechanic" was coming to town 3/28 or 3/31 to look at the car. I'm emotionally disconnected and just want out of this engine-problem-ridden car.
Thanks for your comments though! I'll keep everyone posted.


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## 07 2.5L-emon Wolf (Mar 25, 2008)

*Re: Multiple Knock Sensor issues (gonyofam3)*

gonyofam3:
Yes, I know the NY State New Car Lemon Law well, and it has been really successful since it was enacted here, it is good for comsumers who have legit claims. My Lemonsburg Edition was towed to the dealer 8 days ago for 5th episode of same knock sensor fault code/CEL, etc. I met presumption by 4 failed "fix" attempts. At this rate, I may meet the "30 days in service" requirement when it is really just and "either/or" kind of thing. Dealer service is out of options with VW Tech Line so they told me a "regional mechanic" was coming to town 3/28 or 3/31 to look at the car. I have an attorney reviewing my paperwork and unless VW offers I am starting the process. Honeymoon is over.


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## 07 2.5L-emon Wolf (Mar 25, 2008)

*Re: (KampfGTI)*

KampfGTI:
Interesting, nobody has brought that possibility up yet (between here and other forums I have been looking on), but that is a good one. It's too bad the dealer doesn't read these forums.
Thanks for the suggestion!


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## r-dub (Sep 10, 2005)

*Re: (07 2.5L-emon Wolf)*

i saw you wanted a reply in regards to my knock sensor issue with my R32. rather than buming that thread, since my car is fixed, ill respond here. 
i dont really have much knowlege on the knock sensor issue other than this timeline (rough mileage)
about 3,000 i threw my first cel
about 3,500 it went off
never had it scanned at these periods, (i checked the usual thing(s) that throw a cel, i.e. gas cap)
about 7,000 i threw a 2nd cel
had it scanned, the scan said "knock sensor implausable signal spurratic"
had it cleared
about 7,100 it came back on, had the senor replaced...
i picked up my car, dropped it off at my house, went out of town, came back and a cel came on for a tear in the bank 2 secondary air hose







i wasnt even under the hood while i was out of town, yet they are making me pay for a hose?








so they still currently have my car....if i have any other "knock" issues ill let you know


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## 07 2.5L-emon Wolf (Mar 25, 2008)

*Re: Multiple Knock Sensor issues (07 2.5L-emon Wolf)*

Drum roll please.....
After holding the car hostage 16 days (and a combined 23 days for all the repairs), the VW regional technician determined that the Wiring Harness was at fault. He decided this is what continued to make the knock sensor(s) fail all 5 times in the last 3 months spanning 1200 miles.
In the meantime I have an attorney who is going to help me legally get rid of this car as I have met NY state's lemon criteria.
I feel sorry for whoever buys it. I have read and learned so much about continued knock sensor failure shortening the life of the engine. Buyer beware...and thanks for all of your ideas and help!


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## Mike1ch (Apr 20, 2009)

*Same Problem*

I myself have this same problem.
I have a 2009 2.5 SE Manual.
My knock sensor code appears in heavy rain, and has only happened in these NJ winters.
Granted I have 49,000 miles and had this happen a total of 3 times, I feel like I need to get this taken care of. 

How it happened today. I hit a large puddle in the left lane of a highway, and I noticed my car was in limp mode shortly after. A few minutes later the cel light is on and checked it with a basic scan tool and showed the knock sensor code. 
Curious, has anyone had any other causes to this besides the assumed cause in this post?
This has had to happen to more people...

Thanks


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## mk5RABt (Jul 28, 2008)

basically the ecu is retarding the ignition timing because it thinks the engine is knocking based on the input of the knock sensors which are in all likely hood TOOO sensitive because of the software level...it may just be a batch of cars that ecu's don't exactly match the engines...tell your dealers to run gff and send it to helpline on attached to their VTA...basically like all brands VW only releases what they have to even to the dealers...helpline basically has all the answers...they should be able to check the engine code against the software level of the ecm software and make sure it's right...because if the wires are good and the sensors are good... then someones brain isn't working...unless everyones engine are knocking... and I'm sure we'd have a lot bigger problems on our hands than we do


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## rags2riches (Jan 2, 2010)

I just had similar problems with my 2009 rabbit. Same engine. Turns out I got a tank of gas that was almost 50% water. I saw the sample it was seriously 50-50. I found the source of the problem quickly. I wouldn't think one bad tank would cause problems for this long. However, you might want to add a can of seafoam to your next fill up and then after that try putting some dry gas in with the next few fill ups. Might not be the trouble, but what I recommended was recommended to me by my dealer tech so it couldn't be bad for it.


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