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My 2009 has 50K and it set code PO137. I changed the downstream oxygen sensor, but it's still setting the code. I have a scangauge and I remove the code, but the code returns daily. Performance is fine and everything else about the car seems normal. :banghead:
Any ideas for a remedy?
Did u try to pull the battery and have it reset .
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Yes, I did that when I installed the sensor. As far as I know removal by the scangauge has the same effect in removing the code.Quote:
Originally Posted by jonolach.jl
I'm in the process of doing the same.thing so I hope it doesn't happen to me .
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Hi all,Quote:
Originally Posted by jonolach.jl
Been there, done that. Got the T-shirt to prove it.
Same thing happened to me. I installed a brand new NTK O2 sensor when I replaced the front flex pipe section on my 2009 Aveo. It threw that same code within the next day or two. I cleared the code twice more, but it kept coming back within a couple of drive cycles.
I spent some time Googling the matter, and it appears that the use of non-AC Delco O2 sensors MAY require the car's ECM to be adjusted with a Tech2 tool to accept the new resistance values of the non-AC Delco O2 sensor. However, if you use a replacement AC Delco O2 sensor, the resistance values of the replacement AC Delco O2 sensor will be very close to the factory installed OEM O2 sensor. So you will likely NOT need to use a Tech2 tool if you replace your existing factory O2 sensor with a new AC Delco O2 sensor. So, although I had a brand new NTK O2 sensor installed, instead of getting hosed by my local GM mechanic to do an ECM re-learn, I instead elected to buy a new AC Delco O2 sensor from RockAuto. Installed it, then cleared the code, and I never got that code again. Apparently the ECMs on Aveo's cannot "learn" the resistance values of O2 sensors outside of a very narrow band, no matter how many times you clear the codes or disconnect the battery. If your new O2 sensor's resistance values are outside that very narrow band, you must use a Tech2 tool to manually tell the ECM to re-learn the new resistance values. It was an expensive lesson for me. For me, from now on, whenever i replace the O2 sensors, I will always forever more use an AC Delco O2 sensor.
That's my 2 cents.
Deano.
Guess I'll have to order ac then cause I have a different one coming lolQuote:
Originally Posted by Deano
I think RockAuto has 30$ for downstream right now
Thx
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Quote:
Originally Posted by Deano
Thanks for the insight. Everything you are saying is plausible and probably the case. If so, it's a sneaky
way for GM to prevent the use of aftermarket parts.
Does anyone know how to test the resistances on the sensor? I tried testing the old sensor and across 2 of the pins it read 2000 ohms. I read somewhere that that is the correct value. But none of the other pins gave any reading, and my old sensor apparently is dysfunctional, so it proves nothing.
I bought the new sensor at Rock Auto. It a Delphi (which is made in China). Since they are selling them as a proper replacement for Aveos I'll ask if I can return it for credit towards an AC Delco sensor.
What tools do I need to remove the rear sensor . The one on top of the engine . I can't get to it . So dam hard
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Hi all,Quote:
Originally Posted by jonolach.jl
There is no absolute requirement to use only AC Delco O2 sensors. The Delphi O2 sensor might work perfectly right out of the box, without needing a Tech2 ECM re-learn. You might get lucky. So might any other non-AC Delco O2 sensor. They might work perfectly fine, out of the box, without needing a Tech2 ECM re-learn. But if your new O2 sensor still throws a code, then you either need to use a Tech2 tool to do an ECM re-learn, or alternatively, buy another brand of O2 sensor, and try again to see if it will work perfectly right of the box. But that might get expensive to keep trying other O2 sensors. That's the only reason I suggest stick with AC Delco O2 sensors, especially if you have a 2009-2011 Aveo. However, if you already own a Tech2 tool, or are good friends with a mechanic that owns a Tech2 tool, then buy the cheapest O2 sensor available, and do a ECM re-learn if it still throws a code.
Deano.
Many thanks, Deano, as your advice solved my problem. I returned the Delphi sensor to Rock Auto and replaced it with the Delco sensor, also from them at double the price. The Delco sensor works and does not set any code. Rock Auto provided me with a full refund for the return of the Delphi one.Quote:
Originally Posted by Deano
Most of us don't have access to a Tech2 tool, so for me the easiest solution was to buy the original Delco part.
The one on top of the engine is the upstream sensor. The downstream (or rear) sensor is located in the front exhaust pipe in the center, towards the passenger side. It's easy to remove with a 22mm wrench or a large adjustable wrench.Quote:
Originally Posted by jonolach.jl
The upstream one is in a recess and would require a socket wrench.