Hi!

 

I have this O2 sensor sub-harness off the 2001 Subaru Legacy engine I am converting for my VW Vanagon.  I am wondering, in general, what is it for?  I mean, why didn't Subaru just make the harness long enough to reach the O2 sensors?

 

Also, I stupidly forgot which one (up or down stream) I pulled this off of.  Anybody know?

 

Jason

 

 

 

It's for the downstream sensor.

That section of harness runs along the side of the transmission and joins the main harness at the bell housing. The rear sensor would need a 4 foot long pigtail to reach.

They use the short harness to keep things modular on assembly. That short section is attached to the side of the trans, and connected to the main harness after the engine/trans are mounted in the car.