CEL just came on. Pulled the code and I get:
17516 - Oxygen (Lambda) Sensor Heating: B2 S1: Performance too Low
P1108 - 008 - Implausible Signal - Intermittent


Is this a bad sensor, or something else?

Can anyone tell me where this sensor it?

 

Bank 2 sensor 1 is the pre cat sensor on the driver side. To access it, you need to remove the coolant expansion tank and use a long extension with swivel and an o2 sensor wrench.

Start by checking the resistance on the o2 sensors.

http://www.vaglinks.com/Docs/Audi/Mi...esting_DIY.pdf

 

Your pics and easy to understand instructions may have saved me money and others as well. Thank you

 

Well my volt meter crapped out on me. Ugh. I have been clearing the codes and monitoring them and they always come back B2-S1 Malfunction or B2-S1 output too low. Is it safe to assume that the sensor is just bad?

I did a quick search for the sensor and a lot of the notes state, "OE Type w/Connector Before Catalyst Two Required", i.e.
http://www.partsgeek.com/gbproducts/...ek+Google+Base

What does that mean? Should I replace both the left and right pre-cat sensors?

I assume once I drop the Coolant Expansion Tank I should be able to see the sensor? Anything else in the way I should be worried about? Anyone got any pics? If not I will try to take some when I do mine... here we go!

 

Due to the popular demand, here are some pictures for the bank 1. Bank 2 is pretty much the same other than the fact that you just need to swing away the expansion tank. Be careful because old hoses and connector can break. (Speaking from experience...)

First of all, here are the tools that you will need.


O2 sensor socket, extension, screw drivers, and a pair of scissors or a knife. Don't forget the sensor. Bosch sensors come with a small tube of anti-seize for the threads. Others may not.

Here is a general location of the sensor.



It is below the kombi valve. You will need to remove the air intake hose and air filter assembly to gain access. Here is the actual sensor below the kombi valve.



You see, it is well buried; hence you need the o2 wrench and adjustable extension...

The wiring is held by a few zip ties.



Green arrow points to the connector. Red arrow is a location of a factory zip tie that is connected to the body. I broke mine. There is another one where the blue arrow is pointing to.

Anyways, removal is pretty straight forward. But be careful when you are installing the new sensor! Make sure that you don't twist the wire as you are screwing in the sensor.

FYI, my B2S1 failed shorty after, as in a couple of days, after the B1S1. So I actually decided to replace the rear ones as well. It was an expensive repair due to the parts cost, but considering that average o2 sensor life is about 90 to 100K, and mine was at 105K, they were about due for replacement.

 

Forgot to mention that Amazon sells the sensors for pretty cheap. The front 2 has the same number while the rear ones are different. Front Bosch number is 16287. Rear sensor mumbers are 16067 and 16069. Do a froogle search for cheap prices. But make sure that the supplier is reputable.

 

Dude, that post rocked!

 

when you say rear sensors you mean rear left and right part numbers or rear pre-cat and rear main cat parts numbers?