O2 sensor code help

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Jul 11, 2022 | 08:25 PM

Buddy A

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Melting Slicks

Joined: Sep 2005

Posts: 2,184

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From: Corpus Christi Texas

O2 sensor code help

Hello all. My 2015 Z is running rough. Check engine light flashing. Kooks headers, Halltech, DSX flex fuel and tuned by Pat G. Went to Auto Zone to have error codes read. P0036, P0037, P0056, P0057. So I presumed rear O2 sensors went bad. Looked at them and all looked good. Well I went to swap them and discovered that the shop that installed the headers, for previous owner, installed the rear sensors and just tucked the cables up behind the insulation.
Question: would the front sensors cause these codes?
Thanks

Jul 11, 2022 | 08:52 PM

9sec

Safety Car

Joined: Jul 2019

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From: nashville TN

if the front sensors were not turned off in the tune you need to install foulers and pack them with steel wool in the rear sensors and plugged back in . the rear reading needs to be less than the fronts to keep the lights off

Jul 11, 2022 | 09:02 PM

Buddy A

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Melting Slicks

Joined: Sep 2005

Posts: 2,184

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From: Corpus Christi Texas

It was retuned in August 2021 and had been driving great. I did have it sitting for like 7 weeks

Jul 12, 2022 | 10:08 AM

jaywoo

Racer

Joined: May 2013

Posts: 280

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From: Cabot, AR

Does your car have cats still, or catless? Either way, without those O2 sensors hooked up, your tuner must have turned them off otherwise you would have had those codes immediately. I’m thinking there’s gotta be something else causing the check engine light. You may have to have it go back to your tuner and have him check it.

Jul 12, 2022 | 07:39 PM

Buddy A

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Melting Slicks

Joined: Sep 2005

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From: Corpus Christi Texas

Codes indicate rear sensors which are installed, but not plugged in. Just don't know what else would trip a rear sensor heating error

Jul 13, 2022 | 07:03 AM

Kerviper

Instructor

Joined: Mar 2015

Posts: 145

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From: Reading, PA by way of FL

The rear sensors wouldn’t cause the car to run rough though either way they are only for Cat performance monitoring. They do not control Fuel trims, those would be Sensor 1 on each bank.
Being a tuned car, you need to call your tuner because it could be all sorts of things and it doesn’t seem like you are getting the right/helpful information from the code reader.

Also I believe if you disabled codes with HPTuners; you some times “stop” them by making them “permanent” which causes the car to not perform the test again. Maybe autoZones reader would is picking them up still but not real? Real tuners can chime in!

Jul 13, 2022 | 10:23 AM

Buddy A

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Melting Slicks

Joined: Sep 2005

Posts: 2,184

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From: Corpus Christi Texas

Spoke to the tuner. He suggested I check plugs and wires. Car has 18,000 miles. I was curious if the front sensors would cause these issues? Or maybe I just got some bad gas and Auto Zone reader is leading me in the wrong direction?

Jul 21, 2022 | 07:05 PM

Buddy A

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Melting Slicks

Joined: Sep 2005

Posts: 2,184

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From: Corpus Christi Texas

Update:
Code was a result of the tune. Rear sensors were tuned out. But I guess codes will still show. Anyway. I decided to check the plugs and wires. Found the black plastic cap on the drivers side valve cover was partially removed. Presume someone attempted to remove it for oil change. I could not figure out how to remove it or fully seat it. So I used RTV to seal around it. Car runs well again. Vacuum leak.
Now I need to figure out how to reseat that plug.