B18C2 4 wire O2 Sensor (which wire?)

Hi guys,

Installed my RMF Headers today and everything's good, I had to extend the O2 Sensor wires but when I chopped it off to solder I completely forgot to mark the 2 black wires :eek:

Now I have no idea which is which. Tried searching but haven't really been able to find any info.

I've attached photos so thanks in advance if you can tell me which one connects to what

Attachment 21680Attachment 21681Attachment 21682

you may mix up the black wires... if car dies after it is warm/10-30 seconds, that's the first thing to swap over and troubleshoot.. theres no way to tell one from the other by looking at them

It doesn't matter which is which you can connect the black wires anyway and it will be fine.

Thanks guys that's what I wanted to hear. I just got under the car and switched between the two and both turned off the warning light.

Cheers!