The heater circuit on the front O2 sensor is throwing a check engine lite.  The O2 is brand new from Subaru.  We know that it is behind the glovebox and is brown in color.   But there are 2 brown relays there.  We need to find out if it is the right relay or is it the left relay?  What does the other relay do?

Thanks all,  frustrated Mark

Subaru Factory Service Manuals (FSM) - Every Model - USDM/EU (sl-i.net)

Look up your model and year and go to the wiring diagrams, find it there.

O..

Thank you very much !!!!!!!!!!!!!

We found it and it was not functioning.  Replaced it and 5 min later the brand new Subaru O2 sensor threw a code for low voltage.  Got another one under warranty and now the car works just fine after setting the monitors.   YEAH

 

Mark