QuattroStylez

I've been searching around and trying to figure out something I think is simple.

The pre-cat O2 sensor (S1) is self heating and the post-cat O2 sensor (S2) is not heating? I have a bad S2 and I'm trying to figure out what kind to get for a replacement.

Thanks in advance!

Mrkrad

for the post cat o2 sensor:

4 wire = heated
2 wire = not heated

the audi is really touchy but you could just bust out the ole 89-92 ford mustang 3 wire or find a similar 4 wire they are like $40 at autozone. in a pinch; or get the chip that deletes the this diagnostic sensor (yes it is used only for diagnostics of the cat) and the chip ignores it; and the missing doohickey that usually sits between them and is replaced with a crack pipe

o2 sensors 80K warranty, federal law

MikTip

...<ul><li><a href="http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi/?html=learnmore.html&amp;productID=7012">http://www.ecstuning.com/stage/edpd/pagebuild_v2.cgi/?html=learnmore.html&amp;productID=7012</a</li></ul>

QuattroStylez

I know its a little late, but thanks for the info. Turns out it wasn't a bad O2 sensor. I ended up changing the speed sensor, cleared codes and its been running fine since.