I'm new to this forum, and i'm looking for a little help.

 

I have a 2004 Legacy, with cal emission (EJ259 engine code I think), bought it in Maine.  The car has 3 cats and 5 O2 sensors.  Today, the "check engine" light came on, I got the code, P0043, I checked in my manual, MY2005, and it doesn't list this code? I googled it and it seems to be " heater control circuit low, bank 1 sensor 3" Anyway looking for the Subaru diagnostic test procedure for this code,  This is the step by step follow through that shows you to check all points in the system to eliminate things that could also cause this code to be set.  If someone knows where I can find it, that would be great. Thanks in advance, I'll check back tomorrow.

Crawl under and check the wiring going to the rearmost sensor.

There are two wires the same color, those are for the heater in the sensor. Back probe the connector on one of those two wires and check for 12v reaching the sensor. Be sure to check both.

 

If you google around here for Subaru Factory service manual there are some links where you can download one.