o2 censor wire on a s5
 

i am trying to find out what wire is the o2 sensor wire gooing into the ecu on a s5 if u have any in formation or wiring diagrahms it would be greatly appreciated

O2 sensor is part of the emissions harness. The actual connector comes out near the lower intake. The wire is I believe a gray shielded wire. If the car is turbo, there are two gray sheilded wires on this harness, since one is for the knock sensor. That wire leads directly to the connector at the knock box.

should the O2 sensor wire (mine have no stock "clip" on it) be single wire or double wired comming from the harness?

i have wire-looms and all i can see is this white-ish wire but it was shielded and had 2 wires INSIDE it.... so is that the stock one? or should i trace the harness to replace this wire (if it was modified before i got the car...)