I have an 03 forester giving me the 2 codes for the o2 sensor. I have a 99 outback parts car. I was wondering if i could swap the exhaust system would it "Lego"  together? The plugs the same? Would the ecu be "ok" with it or the sensors give the ecu different signals between the 99 OB and the 03 forester? This is in California and i need to smog the 03 forester 

Ideally we know what codes we're discussing but if we rely on the diagnosis presented here and it is the sensors - why not just swap the sensor instead of the entire exhaust? 

quick ebay search shows the connectors are different. 

maybe you can splice the 03 forester connector onto the 99 oxygen sensors if they're the same number of wires.  

This listing suggests the sensors may be the same but have different connectors:

https://www.ebay.com/itm/New-Bosch-OEM-Universal-4W-O2-Oxygen-Sensor-for-1998-2010-Subaru-Vehicles/380478459845?fits=Year%3A2003|Model%3AForester&epid=7005674554&hash=item5896488fc5:g:Pd4AAOSwajRZboeP

Post the two codes here for better assistance.

When i get home from work i will put the scanner on it. And post the codes

With the ebay item, that makes me wonder what the difference between the front sensor and the back one? 

Front sensor is an Air/Fuel sensor.  Rear one monitors the efficiency of the catalytic converter

But, is the sensor its self the same one? 

P0032

p0032 pd

Not sure what the small "pd" is on the scanner. But that's what it shows. The scanner i used is a Bosch PocketScan

pd likely means 'pending' - some DTCs won't set a CEL unless they have occurred more than once in some period of time.

 

you may have a bad front sensor or bad wiring to it.

 

 

Look up both sensor's on rockauto.com and compare the part numbers. They are almost certainly different. 

GD

i would be willing to put money on them being different.

i know some people have done the "splice" thing, but it has never worked out for me - I will spend the little extra to get the right one with the appropriate connector already on it just to save the headaches.

Thank you everyone for quick and helpful responses 

So with those codes p0032, what would be the way to test wires to it vs the sensor itself? Is the a resistance to test for on the sensor? If so whats the "good" range? The wires supposed to have 12v on one or something? 

Page 6 and 7 give troubleshooting procedure for P0032

Diagnostic Procedure with Diagnostic Trouble Code (DTC).pdf

Ok, i did the procedure for p0032. 

(B136)  number 6 and 17 read 2.7v it asks to shake harness and plugs, does it read more the 8v? No. Then says "end" so im at a lose.