2002 downstream O2 sensor connector

[RobinReliant]

Hello,

 

I have a 2002 Legacy L Wagon. I have a persistent P0420 code, and I'm hoping it's related to the fact the downstream O2 sensor isn't connected!. The wires are clipped short off the sensor.

 

I've looked and looked in the engine compartment, but I don't see an empty connector. The disassembly manual shows a photo, but it's too close to tell where in the bay it is.

[doublechaz]

It's not in the engine bay, it's under the car near the downstream sensor. The bit on the left edge of the photo is the transmission oil pan for an auto trans. Location will be similar if you have a manual trans.

[RobinReliant]

I got under there last night and poked around quite a bit. I'm convinced that a prior owner or mechanic has clipped the connector off too.

 

How difficult would it be to find the connections where they all go through the firewall?

[doublechaz]

It may have been swept away by road debris. A mechanic would have to be insane to cut it off. On my 95 manual trans the sensor wires are part of the trans sub harness. That connects to the main harness at the bell housing/engine joint along with the engine harness. That's where it flies over to the firewall (Subaru calls it the bulkhead in the FSM) and through to the ECU inside. I don't know on the newer units, but there is a good chance it is similar.