Forgive me if this post seems a bit brusque, but, i have been searching for over a week for the answer to what i think is a simple question, with no luck. My question is, which of the 4 upstream O2 wires (2 blacks, one white, one blue) are for the heater circuit? The car is an 04 Impreza Outback Sport, 2.5, non-turbo, automatic. The reason for this is, i have a P0032 code, that, as soon as you clear it, then start the car, it comes right back, and, the car is due for inspection in 2 weeks, and wont pass with a CEL, so, before i spend $195 on a new OEM sensor, i want to make absolutely sure it is the sensor. Yes, i know i can get it a bit cheaper from Rockauto, and even cheaper from Amazon, but, i prefer dealer/OEM parts.

2 blacks will be the heater circuit.

Not sure on the other 2

The factory sensor is made by Denso. There is no reason to buy it from Subaru. They didn't make it nor do they have a corner on the Denso sensor market.

Black wires are heater element. White is sensor ground, blue is signal. 

GD

Edited April 14, 20196 yr by GeneralDisorder

9 hours ago, GeneralDisorder said:

The factory sensor is made by Denso. There is no reason to buy it from Subaru. They didn't make it nor do they have a corner on the Denso sensor market.

Black wires are heater element. White is sensor ground, blue is signal. 

GD

I already picked it up, i just haven't installed it yet. I planned on doing it today, until it started pouring out.