Ok got a 96' legacy ej22 and on the way to school this morning got a CEL when i got home i pulled the code P0136...02 Sensor Circuit Malfunction ( Bank 1 Sensor 2 ) i was wondering if i should do any testing on this sensor before i go ahead and replace it? oh the car has 187,500 miles and at about 170,000 the exhaust broke off(long story) so the person who owned it just cut the o2 sensor...i have sense soldered the correct wires back together and it was all fine until now. for some odd reason i think this is the origional 02 sensor......any help would be appreciated.....

I would check your solder connection

but

I'm afraid it's time.

thanks....by the way which one is sensor 2 is it the one that is in/right after the rear cat?

It could be the connections since it says circuit malfunction. Of course the sensor itself could be open/short/etc causing 'circuit malfunction'. I have a '96 2.2L too which I got before I knew about Subaru dealers selling parts online, so I bought a bosch universal solderit yourself (I could have had a new OEM with the right connector for the same price!). It has been working ok for the last few years though....

 

DTC PO136: REAR OXYGEN SENSOR CIRCUIT MALFUNCTION (R02-V)

 

The rear o2 sensor is the one in/near the rear cat. You can see it here in the top centerish of this pic (though this is '00 obw)

shame on me AGAIN!!

I'm given this helpin' stuff up until I learn to read!!

 

Sorry EVO, listen to the Porc he has his poop in a pile.

 

I missed the "Sensor 2"

 

 

I would assume the sensor needs a heater circuit to keep from

tripping the CEL?

Thus a univ. single wire will not work.

 

Can you confirm or refute this Porc?

hehe....I thought front o2 at first too (that's why my post is edited )

 

Not sure if this rear o2 has a heater. I have a new OEM rear o2 for this vehicle I could check out to see how many wires it has. It is either 2 or 3 iirc) (the bosch I mentioned earlier was the front, it was 3 wires IIRC).

Not really on topic, but I just changed

the front which has a heater

(that is what failed on mine)

 

It's a four wire. 2 for the heater and two for the

A/F ratio (02 content) signal, I assume.

 

edited to add it's made by Denso

i believe my rear 02 sensor is 3 wire....thanks for the help guys......i erased the CEL.....so if it comes back i will replace the sensor.....

ok so i got another code today a P0139 (O2 sensor signal slow bank 1 sensor 2)......my question is.....what is the likelyhood that the sensor is bad.....the first code i got was a P0136 (02 sensor circuit malfunction bank 1 sensor2) and now P0139 (02 sensor signal slow bank 1 sensor 2 )....from what you guys have seen is the most likely cause a faulty sensor?.....i just want to double check before i go spend the $130 at Subaru for one......thanks again for all your replies....