Hello !! just bought an S6 V8 4.2Lts and is trowing the following codes:

17538 - Fuel Trim; Bank 2 (Mult): System too Lean
P1130 - 35-00 - -
17536 - Fuel Trim; Bank 1 (Mult): System too Lean
P1128 - 35-00 - -
17539 - Oxygen (Lambda) Sensor; B2 S1: Internal Resistance too High
P1131 - 35-10 - - - Intermittent
17549 - Load Calculation Cross Check: Implausible Value
P1141 - 35-10 - - - Intermittent

my question is where is the B2S1 sensor located?, I removed the engine covers but couldnt locate any I just want to know if I'm going to be able to change it or Im going to need to go to some mechanic.

This is my engine...


thanks!

 

i am fortunate in that i have never had reason to find out exactly where they are. That said, answer #1 would be "buy the service manual from Amazon". My next would be - we can guess where they MUST be. One Before the cat and one after. So follow the manifold from the exhaust valves down, and find the cat. One must be B4 it and one after. The work as follows: the DELTA between them indicates the efficiency of the cat. The primary ( i think, i may be wrong) is the main indicator of fuel trim (its a negative feedback loop).

The screw into the exhaust. Generally located where one can't access them.

G

 

The O2 sensors of course are down on the exhaust header pipes--the front ones that is. You can just barely see them (maybe...) if you look about a foot down back at the far rear of the motor on the two sides. A better view requires pulling the air box, MAF and intake tube that leads to throttle body. Even then, my experience is you literally have to get on top of the motor to reach down to get them, and its essentially blind/all by feel, at least on one of the two.

Meanwhile though, before heading there, simply check your vacuum lines. The bank too lean code stuff if often very simple vacuum line problems, particularly those that control the secondary air injection. Another clue is a very slightly rough cold idle. Look especially at the lines under the decorative center intake manifold cover toward the driver's side cylinder head. There is a vacuum controlled valve in the center there, and those vacuum line often cook and fail. Also, look at the ones that drop down behind the motor toward where the secondary air control valves actually are. Again, likely to rot out. Big picture, the German braided 3mm vacuum hose might be pretty/quaint to look at, but it is junk long term. From experience, eventually you will replace it all--about 15 feet in total of good branded stuff (gates, etc.), off a reel at a decent parts store. Just do it a piece at a time, and you can't go wrong on routing. The hood also has a sticker with the diagram you can look at.

Net, I would start w/ the vacuum lines before any very difficult to get at and more expensive O2 sensors.

 

the pass side O2 is near impossible remove. The drivers side is easy, its straight under the coolant tank.

 

search the forum rather than ask ??
There are many threads involving removal of 02 sensors involving extensions, duct taped swivel extensions, go in from top, use an 02 sensor wrench.

 

I already searched but didnt found anything with photos for the V8 engine just a great post for the 2.7t. anyway I found it


Hello! yes! I found that the other day! I removed the tank and the sensor is down there so thats B2 S1 !!!

Hello thanks for the advice! I just bought the sensor on friday, I'm going to change it tomorrow and then check if the codes are gone if not then I'm going to check the

 

Good on you. If you can see it you're halfway there, minus the blood sacrifice/skinned knuckles.

 

grrrrr I better wear UFC gloves then...

 

Hello guys! Well I made it! New sensor installed and also some vacuum lines were all cracked and I had one disconected :S

New Sensor - Bosch 0258 003 813
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Old sensor, all red! I had some vacuum lines broken according to some readings this could be the cause, also its a different bosch part from the one I bought I hope this doesnt affect... any toughts?
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New sensor installed, I lubricated with WD40 to remove the old one thank god ... there you can see one of the broken vacuum lines
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Old sensor and old vacuum lines old f@#$@$
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Initial toughts after like 7kms with the new sensor, Im from 15.8 lts/100km to 14.4 lts/100km I think the ecu needs to adjust parameters and hopefully improve my gas mileage.

 

Great pics NAC5000, and good job! How are you going to spend the $1000 you just saved (compared to taking it to the dealer)?
Did you figure out what vacuum line it is? I can't figure out what it does from the pic.
Here is a good site with info on How to decode OEM VW part number and Audi part numbers, maybe you can ease your worry if the differing O2 sensor numbers were due to a normal revision/upgrade.
MP4.2+6.0, good call on the vacuum lines!
MP4.2+6.0 do I know your name or do we call you MP, sorry if I forgot it because you are really a top contributor to the A8 forum.