Help with identification of wire

[Cdnbimmer]

I have a 1992 318i vert and just recently removed the cover on the firewall revealing the wire harness under it. I found one grey/black stripe wire disconnected under it. It is directly infront of blower motor on top the the wiring harness. Any ideas what it is for? Should I plug it back in??

[E30 Wagen]

I can't remember what that wire is for but I'm pretty sure it's supposed to be left unplugged.

[bmwman91]

If your car is equipped with an O2 sensor, then leave it unplugged. That is the LLCO (low-level carbon monoxide) signal, which comes from the air flow meter, but it is NOT used on cars with O2 sensors. Plugging it in has caused many an M42 owner to have terrible warm-running issues since the ECU ends up using unnecessary fuel calculation factors.

[twright]

If your car is equipped with an O2 sensor, then leave it unplugged. That is the LLCO (low-level carbon monoxide) signal, which comes from the air flow meter, but it is NOT used on cars with O2 sensors. Plugging it in has caused many an M42 owner to have terrible warm-running issues since the ECU ends up using unnecessary fuel calculation factors.

What he said.

[Cdnbimmer]

Ok thanks. Yes my m42 has an oxygen sensor. I’ll definitely leave it unplugged!!