CODE P 17544... fuel trim too lean... hellllllp.

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Nov 7, 2010 | 02:57 PM

Raudi225

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CODE P 17544... fuel trim too lean... hellllllp.

I've had my CEL on for a couple of months now. I don't notice anything different with the car just by driving it. Friday night after replacing my O2 sensor, my brother/mechanic took my TT on a test drive and ran diagnostics... apparently some weird stuff happened. It would not communicate with his software and actually kicked him out of it several times, and the car started misfiring badly. It is okay now, but needless to say the CEL is still on.

I have been pulling a fuel trim bank 1 system too lean code for a couple of months now (P 17544). I was also pulling a code for the O2 sensor resistance too high, so we replaced that Friday night and this happened. I can't give a full print out because of what happened... but the P 17544 has been stored in there for awhile.

I desperately need some solutions. Any ideas? Car is a bone stock 2001 Audi TT 225 Quattro Coupe, AMU engine. My brother said worst case scenario, new ECU since it wouldn't communicate with his software... best case scenario, maybe a vacuum leak? He is refusing to touch it further so I am going to have to drive it four hours to the closest dealer, and I would like to have some kind of idea what services I should be expecting ya know...

Any help is GREATLY appreciated...

Nov 8, 2010 | 08:59 AM

J. Patterson

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The most likely cause is the MAF, but a vacuum leak could do that too although those usually manifest themselves as boost leaks and affect power output. If it has not had a MAF it cant hurt at that age. You'll need a pressure tester to check for boost leaks but there are some likely hoses to check under the intake manifold and at the fuel pressure regulator. In fact you should check that hose first, It is the fabric covered one. Many reports of their degradeing and spliting.

Nov 12, 2010 | 03:18 AM

CTallroad

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can anyone post the link to how to reset the trims?

My 02TTqc just had the battery disconnected for 12 hours (replacing the stupid brake switch again...) and now the throttle response is annoying/out of tune. When shifting it holds the gas on after I've released the throttle (making shifts slow and not smooth) and it's got a slow response to blips like when you are down shifting.

All I can think of is that the trims got reset while the car was idling in the shop, and if I reset and then go drive maybe I'll fix it..

02ttqc
102,000

Nov 14, 2010 | 06:18 PM

BigBob00'TT

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It is not the MAF. It is a vacuum leak. Any kind of code that comes up saying system is too lean has something to do with too much air flow resulted from a leak in your vacuum lines.

Nov 20, 2010 | 09:18 AM

TTschwing

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Incorrect.....It can be either....>

Quote:

Originally Posted by BigBob00'TT

It is not the MAF. It is a vacuum leak. Any kind of code that comes up saying system is too lean has something to do with too much air flow resulted from a leak in your vacuum lines.

It is often the MAF as it looses it's ability to measure air flow over time. A MAF with Anything more than 50-60K on the car is suspect.
Cleaning doesn't help as it's surface degradation that results in them getting weak..