# CEL Code: P015B: H02S Delayed Response To Lean Sensor 2



## EricSmit (Dec 21, 2016)

On top of the midpipe.


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## ChevyCanuck (Sep 27, 2016)

EricSmit said:


> On top of the midpipe.


So if my googlefu is correct, the midpipe is part of the exhaust system well past the engine. 

So this rules out the body shop and might explain the super loud rattle I heard a few days ago when starting the car...

Thanks EricSmit!


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## EricSmit (Dec 21, 2016)

No problem. When you get under the car, you'll see the exhaust layout. There are two pieces i'll use as reference:








that is your second cat and resonator. 








and that is your flex pipe. 

the o2 sensor you are looking for is in between them.


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## ChevyCanuck (Sep 27, 2016)

EricSmit, that's awesome. Thanks for sharing those photos!

I have an appointment with the dealer next week to check it out. I'll leave this one to them as I don't have access to a lift plus I imagine this has to be covered by the warranty!

Cheers.


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## EricSmit (Dec 21, 2016)

No problem bud. Good luck.


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## ChevyCanuck (Sep 27, 2016)

So just a quick update. Went on a quick burger run and sure enough the Check Engine Light is now off. I guess the issue resolved itself. I still have to being the car in next week for the center stop lamp recall and oil change so I'll make sure to mention the CEL to the dealer. I'm not very confident it's resolved for good...


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## EricSmit (Dec 21, 2016)

it turned off so it could resurface when you aren't looking. [emoji23]


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## ChevyCanuck (Sep 27, 2016)

Final Update:

Just had a visit to the dealer for stoplamp recall and an oil change. They checked the codes and went and replaced O2 sensor #1. My OBD reader read sensor #2 but it could be wrong I suppose as it has older 2015 software/database?

So other than having to readjust my seat and mirror [email protected][email protected] all is well! Great service from the dealership.


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