DIY: Post Cat O2 Sensor

[fly300kts]

Hi Guys,

For a while now when checking the codes, P0139 or P1114 where popping up:

P0139: O2 Sensor B1 S2: Response too slow
P1114: O2 Sensor B1 S2: Internal resistance too high.

I had enough and decided to replace it. The Dealer wanted almost $200 for the part. I found a direct replacement (same Brand, Bosch with connector installed, at http://www.autopartswarehouse.com for $85 shipped)

So here is my DIY:

Time: 1.00 Hr
Difficulty: 3

Tools:

Torks T25
Ratchet + extensions
22mm Hydraulic wrench ($9.00 for the set at Harbor Freight)

First, how the wrench looks like



The post cat O2 sensor location



Disconnect the connector located right behind the coolant reservoir (Color Brown)



Then, to clear the wrench length, remove the heat shield hold in place with 3 screws.
First one



Second one



Third one (this one will require the ratchet extension)



Now the heat shield is out of the way



And you have plenty of room now for the wrench



The old one was in pretty bad shape



The threads of the new unit come already greased with anti-seize. When you install the new unit, make sure that you don’t pollute the tip of the sensor.
Tight the new one in place, reinstall the shield, reconnect the connector, clear the codes (if any), and your are done

Let me know if any question

Phil

[AudiTFSI3o3]

great write up

[Insane_Audi]

well done :)

[myb5quattro]

wow, great write up

[fly300kts]

Thank you

Phil

[JRMSLINEA4]

Looking forward to knowing if this fixes your car.

[DrZEUS]

Super old thread but I am about to do this (got the same codes). Could you clarify which O2 sensor you purchased from that site? Thanks.

[waiapasi2006]

As always phil. Great DIY.

[Okedokey]

Necro bump, however is there any benefit from removing and cleaning the sensor even if you don't have codes?