It’s my downstream o2 sensor (after cat) I’ve replaced with oem sensor & attempted to reset CEL it pops back up almost immediately. I then checked the fuses no issues there. I then visually inspected the wiring (as best I could) that’s underneath near the front passenger wheel & also did from above in the engine bay. If I’m standing in front of the car it’s at the left rear near the wheel well. I do have a voltage meter but wanted some advice on testing the wiring. Also assuming that test comes back fine then it can only be a bad ECU ? Or can it still be a wiring (ground) problem ? I truly believe it’s a grounding issues myself. I’ve also read that it needs to be driven in order to “reset” the CEL but I don’t believe that to be true but that’s why I’m asking. Thanks in advance

a possible wiring diagram of the o2 sensor to the ecu would be helpful. I was going to rig it directly to the ecu & see if that fixes the issue.
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What are the wire colors at the harness for the O2 sensor?