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Discussion Starter · #1 ·
I'm trying to figure out the cause of this blasted code that keeps coming up on my wifes 2011 traverse. I've tried several things that i've read here, and elsewhere for the same engine, etc... Here's whats been replaced at this point:

Bank 2 Cam Cover
All 4 O2 sensors
PCV hoses, and fittings

Everything I've read points to the PCV system, which the new cam cover should have corrected. I noticed something a moment ago though, that may point to an issue as it seems really strange. The upstream o2 sensors read between .08 and .8 volts according to the PCM, fluctuating as they should. Both waveforms for the voltage on both banks are nearly identical to each other. The downstream sensors however are the strange ones. Bank 1 reads a nearly consistent .65 where the bank 2 downstream reads also nearly consistently .09. Could I be dealing with a bad downstream sensor, causing this whole mess? Or am I barking up the wrong tree entirely...

Thanks for your input!!
 

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Super Moderator
2020 High Country
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1,266 Posts
When it comes to the position 1 O2 sensors, the ones closest to the engine, look at the STFT. Short Term Fuel Trims instead of voltages. STFT should be cycling between -3 and +3 if sensors are working within the normal range. Most readings will the closest to zero with healthy sensors. STFT shows actually how the sensors are controlling the fueling.
Position 2 just monitors cat performance only.
None GM sensors are not reliable.
|What are the Possible Causes of the Code P2179?
  • Intake air leaks
  • Faulty front heated oxygen sensor
  • Ignition misfiring
  • Faulty fuel injectors
  • Incorrect fuel pressure
  • Lack of fuel
  • Faulty Mass Air Flow (MAF) sensor
  • Incorrect Positive Crankcase Ventilation (PCV) hose connection
 

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They mean sensors youd get if you bought from dealer parts center
Usually in a gm box or acdelco oem box.
With gm and acdelco part numbers on label.
Manufacturer may vary.. but items built to gm specs.
 

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2010 LT 3.6L AWD
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Thanks--i felt that deserved clarification.
I'm sure Repairman is aware there are parts available outside the dealer network that exceed oem specs.
Oem parts are often low-bid components that meet minimum specs but at least you should be assured you're getting something that works, and isn't an imitation.
 

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2020 High Country
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Thanks greenT, for correcting my typo.
Genuine GM sensors only for any sensor application. I use Rock Auto to source my sensors which get drop shipped from major distributors. Tons of knock off parts on Flea Bay and Amazon. Lots of knock off NGK labeled spark plug as another example, they have info on their site on how to identify them.
Key is to buy from reputable dealers.
AC plugs always run better than other brands in GM engines, that I've learned the ''easy'' way.
Exceeding Mfgr. specs is just marketing hype.
 

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...
Exceeding Mfgr. specs is just marketing hype.
I don't think you really believe that.
I'm not talking just $20 sensors but suspension, performance parts, chassis parts, fluids & additives, lighting, etc.

My 2nd career, since 95, has been working in the transportation testing & validation business for tier-1 suppliers and accredited 3rd party testers. There wouldn't be much need for such businesses if there wasn't room for improvement.
 

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2020 High Country
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Sure I do. Exceeds mfgr. specifications is marketing. Caveat emptor supersedes everything.
No way for average consumers to verify such claims.
True there is always room for improvement. 46 yrs as an on-site mentor tech I can't count how many components I've seen labeled Rev. H or higher. and still failing. Especially globally sourced.
 

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Discussion Starter · #10 ·
The sensors are all delco. I learned that with my several Saturns I’ve owned over the years. The fuel trims short term fluctuate between about 0 and 10. Long term is the one that’s out of whack with bank 1 fluctuating between 0 and about 10 if I remember correctly and bank 2 going as high as 45 to 50. I’ve also read in another forum where the injectors could very well be the cause of this thing. When I’ve cleared the codes, I occasionally see misfires across bank 2. In a normal engine I wouldn’t think to look at the injectors. But this isn’t a normal engine being direct injection.
 
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