Loosing power - going into safe mode
 

Hi all.

I have a problem with my 00 S4.
Sometimes the car looses power and goes into somekind of safe mode.
It's like the turbo's are not in function / or tuned down.

When I take of the battery cord for about 30 sek, the car functions correctly again.
Then I can drive for some time and the same thing happens again.

Does anyone know what can cause this problem?

Thank you

RE: Loosing power - going into safe mode
 

is there a check engine light?

RE: Loosing power - going into safe mode
 

No, there is no warning or anything else.

RE: Loosing power - going into safe mode
 

Do you have access to a Vag-Com diagnostic cable?

RE: Loosing power - going into safe mode
 

No, I wish I had.... But you have never heard of the problem before?

RE: Loosing power - going into safe mode
 

I have an S3 with thae same problem. The dealer wanted to replace the cam shaft tensioner unit but i declined the offer!! They cleared the fault on the ECU and now it is fine. Is there a ticking from the car on start up?

RE: Loosing power - going into safe mode
 

I know what's wrong.

This JUST happened to me, for 3 months.

Alright so you car feels underpowered but still does everything properly and there is NO check engine light or even any code that a regular OBDII scanner would read (VAG COM is a whole different story)

Most likely because this is what I had was a small boost leak. Small enough for the ECU to put you car into "limp" or "safe" mode. The boost is turned down to about 6 psi but everything functions normally and no check engine light or codes are thrown.

My car is an 01 with 50k miles and the stock Y hose that connects the two stock plastic Bi Pipes to the throttle body was torn underneath the hose clamp. The narrow stock clamp along with the composition of the rubber used in the Y hose have lead to many failures of this hose.

My hose leaked just enough to put the car in safe mode but not enough that I lost all of my boost. I have a boost gauge and it never went higher than 6 and when I fixed the hose it went back to 11-12 or what it should be when not in limp or safe mode.

If you have a boost gauge it is easy to see, other wise a boost leak tester can tell you, they are like 30 bucks shipped, but if you take off the center engine cover and undo the hose clamp I would bet you that your stock boot is indeed torn and needs to be replaced.

I just had an APR Bi Pipe installed and that is the only way to completely eliminate the Y hose and eliminate any possibility of the failure. I also have a Samco hose that replaces the failure prone stock unit. These are normally about 100 dollars and I happened to pick it up off eBay for 30 bucks. It is far superior to the stock unit and is cheaper than the APR Bi Pipe.

I would strongly caution you to NOT to mess with the stock hose unless you have a replacement, because when I did I was not able to make the stock hose function again(and trust me limp mode is much better than no car at all). It was so torn that it would not go back on the throttle body. My car was out of service until I found and had the Samco hose shipped to my house. I would be willing to sell you the hose with appropriate hose clamps for cheap as I do not need it anymore.

If you want to go for the Bi Pipe option Mike at Pure Motorsport got me set up, he is very knowledgeable and was extremely helpful, I would highly recommend you talk to him if you have anymore questions, He even installed it on my car, awesome setup, I would recommend this course of action if you can afford it and never want to have to deal with this problem again, especially if you plan to raise boost levels in the future.


Sorry for the long post but I hope it saves you some headaches that I encountered.

RE: Loosing power - going into safe mode
 

First of allSORRY i bumped this thread but i have to:D

i noticed my s4 is not going like it should ( i have 265pk european version)
so i went to the garage where i bought it (not audi garage but here garages MUST give you 12 months guarantee!

My car has default lambda in bank 2 said the vagcom(i don't have it but my garageowner has one)

My car TICKS like hell when cold start, it sounds like injector ticking but it's harder, it can go away like that and can come back in an instant or stay away for awhile, sometimes it's gone for 10 min, then it's back. it's mostly when ii first start her, but can also come back when the car is warm what's up? it does not come from the head of the car, i hear it clearly and loud when i hold my head near the right wheel (passenger side)

tmorrow my car is back in the garage, i still have guarantee so i want this to be fixed !!!! can someone please give some advice i can tell the garage owner so he knows better where to look, he has all manuals and vagcom and he works only on vw and audi but he told me honestly that he never works on s4-rs4 and that sort of cars...


as for last here is a short clip of my stock s4 with default lambda from 30km/h - 200km/h (it takes TOO fucking longggg)

http://nl.youtube.com/watch?v=do8XFngIrJ4







THANKS GUYS ;)

RE: Loosing power - going into safe mode
 

no one?

RE: Loosing power - going into safe mode
 

no codes? I doubt its the o2 sensor-more like a bad MAF, unplug it and see if you can rev freely above 4k and check vac lines