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I have a friend with B5.5 2001 1.8T and has this code
17536 P1128 Long Term Fuel Trim mult.,Bank1 System too Lean

Any one knows what it is? he change the 2nd O2 sencor but the code came back....
 

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I have a friend with B5.5 2001 1.8T and has this code
17536 P1128 Long Term Fuel Trim mult.,Bank1 System too Lean

Any one knows what it is? he change the 2nd O2 sencor but the code came back....
Well, the second 02 sensor only checks to make sure that CAT is working properly, it's the first you'd want to change, as that monitors the A/F ratio.

A simple google search yields this: http://wiki.ross-tech.com/index.php/17536/P1128/004392
 

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When mine had that error I believe it was the MAF
 

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First thing to check is the four vacuum hoses. If those haven't been replaced, I'm surprised they haven't failed earlier, since the car is from a year with the crappy ones. That was my first such code failure. A year later, my MAF went bad, same code. It can also be caused by a leak in the "L" hose, and maybe by the front oxygen sensor. Start with the vacuum hoses -- cheapest and most likely. Look/listen for small leak/crack, or just go ahead and replace them -- 10 feet of high temp silicone hose, and maybe some small cable ties to clamp it on (reported as not necessary, but I used metal clamps).
 

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x2 on the vacuum hoses. A bad mechanic, or one set in his ways from the early days of electronic engine management, will assume any DTC is an O2 sensor. Lean conditions are nearly always as a result of vacuum leaks.
 

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x2 on the vacuum hoses. A bad mechanic, or one set in his ways from the early days of electronic engine management, will assume any DTC is an O2 sensor. Lean conditions are nearly always as a result of vacuum leaks.
Indeed.


I wasn't suggesting that changing the O2 sensor would solve the problem, more so that if it were to fix it, the wrong sensor was changed.

Generally it's a vacuum line causing this problem. The easiest way IMO to check (tho not 100% accurate) is the run the motor and take a listen to it. A vacuum leak sounds just like a vacuum (go figure) so at least you can narrow down the problem.

Try this, take a pic of where you think the noise is coming from, and we'll see if it's in a commonly troubled area.
 

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Sounds like unmetered air on the intake side causing a lean consition. Check MAF, vacuum hoses, intake plumbing, etc.
 

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Try this, take a pic of where you think the noise is coming from, and we'll see if it's in a commonly troubled area.
You could always use the "******* stethoscope"- a length of 1/2" hose from your ear to various areas of the engine you wish to probe. The noise will change in volume when it points in the direction the sound is coming from.
 

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You could always use the "******* stethoscope"- a length of 1/2" hose from your ear to various areas of the engine you wish to probe. The noise will change in volume when it points in the direction the sound is coming from.
oo...simple, yet effective...

I like!

heh, learn a little sumthin every day....

:D
 

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You could always use the "******* stethoscope"- a length of 1/2" hose from your ear to various areas of the engine you wish to probe. The noise will change in volume when it points in the direction the sound is coming from.
Sorry, that can only be used South of the Mason-Dixon line :lol:
 
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