My check engine light came on so I checked the code and it looks like I have 2o2 sensors that need to be replaced.

The codes were P0155 and P0135. Bank 2 sensor 1 and bank 1 sensor 1.

I love fixing things myself but I need some guidence on this one. Where are the sensors located on the engine? Are they replacable from the top of the engine or from the bottom?

Any help would be greatly appreciated.

thanks

 

Hi,
The o2 sensor on your A6 will be located at the exhaust, the upstream o2 sensor is located before the catalytic converter, while the downstream sensor is connected after the catalytic converter. These sensors look like small plugs connected with wires. To remove them, you'll need to jack up your car and go underneath the vehicle. You cannot remove them from top of the engine. I hope this info will help you out.

 

The front O/2 sensors are accessed from the top , they are a bitch!

 

Now I'm confused. Can they be replaced from the top or the bottom? I have read several different posts. My engine is the 4.2 v8. What am I looking at for time?
Thanks

 

I did the drivers side o2 sensor last night. It wasn't that bad. It took longer to splice the wires than it did to remove sensor. Now for the passenger side.

Do you have to remove any of the exhaust for this side?