# P0171 System Too Lean (Bank 1)



## manzarek (Jun 24, 2009)

I have a 2002 Audi TT 1.8T FWD. About a month ago I backed out of the drive and the front bumper caught on ice that was sticking up at the edge of my drive way. It split the bumper on the underside and jammed ice up in front of my radiator. Later that day the CEL came on with the code "P0171 System Too Lean (Bank 1)" I took it to Kelly's Automotive in Bloomington (SUDs the local Audi dealer had a several week wait... no suprises there) to get the car looked at. The mechanic said that he could find nothing wrong with the car and cleared the light out. A couple days later the light came back with the same code. Again I took it to Kelly's and again he could find nothing wrong. Cleared the light... same story came back on a couple days later.

Can anyone offer some guidance on what this could be? The mechanic assures me it is not a vaccum leak or the MAF. I have no clue where to go from here. Any help would be appreciated!


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## hotgrass (Aug 22, 2008)

when mine did that, it was my hoses under the intake manifold, it was all cracked up.


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## manzarek (Jun 24, 2009)

Was it connected to part of the PCV system?


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## hotgrass (Aug 22, 2008)

yeah, i think so. it was a bunch of hoses cracked.


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## Doooglasss (Aug 28, 2009)

I'd like to make a sticky on this forum titled: "all problems are fixed by finding and repairing vacuum leaks"

body would read:

Even if you think your problem isn't related to a vacuum leak, you problem have a vacuum leak. If someone has told you don't have a leak, you probably have a vacuum leak. If you have pressure tested your system and didn't find a leak then you have a small vacuum leak somewhere that you haven't found yet.


In all seriousness your code points to a leak and only a leak. Someone cannot just look and tell you that you don't have a leak. Some of these cars are going on 10+ years now and have original rubber hoses from the factory overseas. Clamps dig into the rubber and cut it, stuff rubs against it, heat melts it, hot/cold cycles crack it and bad mechanics forget to reconnect stuff.

Under the intake manifold is a key place to look. If you still have a braided FPR hose get rid of it immediately. If you have a boost gauge installed with a plastic hardline check the line hasn't cracked and that it's seated in the gauge correctly. The brake booster hose on the passenger side of the intake manifold (225's) it's a Y junction and is know to crack on the side you cannot see until you remove it.

The easiest way to find them is with a modshack pressure tester. www.modshack.info - even with that tool you need lots of patience and go over everything carefully & slowly.


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## manzarek (Jun 24, 2009)

Thanks for the feedback. I spoke with a friend who is a VW tech and he also said it is def a hose leak. He reccommended checking the intake hoses that are located near the front of the car (i.e. where the ice was jammed). I'll take it back to the mechanice one last time with this suggestion. 

Does anyone else have anything to add?


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## hotgrass (Aug 22, 2008)

go somewhere else, search for a better mechanic :beer:


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## manzarek (Jun 24, 2009)

If only it were that easy... only two places in town work on them. The dealer is one and they are shady (worst track record on BBB that I have ever seen) and this place is the other  I may have to take it out of town.


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## manzarek (Jun 24, 2009)

Back to the mechanic today. I stressed that they should look into the intake system. Let's see how it goes... will keep you posted :snowcool:


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## bb-tt (Jul 2, 2013)

*Greatest advice ever!*



DougLoBue said:


> I'd like to make a sticky on this forum titled: "all problems are fixed by finding and repairing vacuum leaks"
> 
> body would read:
> 
> ...



Thanks Doug!


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