Hey guys Im having these two codes coming up. P0154(Bank 2 sensor 1 Heated oxygen sensor) and P1120. Everywhere I've looked says o2 sensors but wanted to double check here. I was also curious as to how I could tell which sensor is bad and where it's located. Also, how difficult is the job? Any links or suggested websites for the parts? Any help is greatly appreciated! Car is a 2000 A6 2.7t Quattro 6 speed.Thanks!

 

Bank 2 is the driver side. Sensor 1 is the pre-cat sensor. You can pick up the sensors pretty much anywhere. A lot of folks prefer to just pick up a universal 4 wire sensor and splice it in. The direct plug in sensors tend to cost a fair bit more and don't really make a difference.

How difficult a job? Have you done any work on your car before? The basic premise is not that difficult to understand. Wrench out the old sensor unplug it, wrench in the new sensor, plug it in and Bob's your uncle. That is the theory anyway. In actual practice it is a huge PITA. the pre-cat sensors are pretty much right under the firewall at the back of the engine. If you can rotate your coolant tank out of the way a bit, you can sort of barely see the sensor you are looking for. The best way to get a sensor socket on it is to stand on the passenger side of the car near the firewall and attack about 3 long ratchet extensions to your wrench and go at the sensor that way, across the top of the engine. be prepared to be frustrated.

feel free to ask for specifics once you see what the job entails

good luck

have fun

 

Thanks for all the information! Would the single sensor correct both the codes im getting? Ill pm you if I have any other questions, thanks!

 

if you are looking to PM questions to someone, we do have some forum members that are "Tech Guru"s. It will say that under their name. I'm just an enthusiast. please don't take my advice as gospel or anything. I do all my own maintenance, so I do know a good bit, but I'm not even close to being in the same league as those guys.

anyway, most likely replacing that single sensor will take care of both codes. P0154 is the sensor code. the other code, is a fuel trim code, if I'm not mistaken. getting the correct O2 sensor in place, should correct the fuel trim issue you are having. (as I understand it, see previous paragraph)

best of luck

 

Chances are the O2 will take care of the problem. P1120 is an open heater circuit in bank 2/ probe 1 (O2 sensor 1). 99% of the time it is the actual heating elemnet in the sensor has burned out and NOT a vehicle wiring problem, especially when it's just the one sensor showing a fault. A P0154 means no sensor activity detected and a failed heater will cause that. Since it is, as Beau says, a huge PITA even with all the correct tools I'd HIGHLY recommend using only a genuine part. I know, they're $$$$$$ but also remember they're wide band sensors and they are pricey. Just my experience, I've seen way too many aftermarket "universal" sensors fail prematurely or just plain not work right.