Where does the o2 sensor ground connect to? I know it is ground, but trying to find out where the D6 Tan wire actually is connected at.

What car do you have? I got an 89 iroc and I lost my o2 sensor ground awhile back. According to my chiltons manual wiring diagram, the o2 sensor ground from the ecm is attached to the back of the pass. side head. In the diagram, it shows the wire coming from the ecm and attaching where the ground strap is on the back of the pass. head. Very tough to get to. I fixed my ground problem just by tapping a new piece of wire on the tan wire and running it straight to ground and wallah, my o2 started to work. Did this till I can fix it right.