P2A00 - A/F Sensor Circuit Range/Performance (bank 1 sensor 1)

jwick

I know this is not technically a FI problem but I'm opening it here because I am only looking for FI based feedback on the code.

What's happened:
- In early July the referenced code was thrown. The car had ~46k miles on it so I figured it was probably a bad O2 and ordered the new part. Deleted the code and babied it back and forth to work until the sensor came in. I would say I put between 150-200 miles on the car after I cleared the code.
- Receive the new sensor and replaced it.
- Drove for 400-500 miles and the code came back yesterday. (so roughly 600 miles between codes and a new sensor)

How it runs:
- Car runs exactly as it always has since my tune (roughly 2000 miles). Idles fine, closed loop and open loop acting as normal.

What I've checked:
- Sensor plug is firmly seated into its socket
- Wiring was good when I put it in and I covered it with a Thermo-tec sleeve to make sure heat was not an issue (it is the O2 sensor that basically sits less than a foot from the cold side of the turbo). I can't see there being any melting issues on the harness. Item to note I had not wrapped the original sensor when I did the turbo install and when I removed it the wiring for the sensor still looked perfect.
- Checked all silicon couplers on the intake piping, no leaks I can see
- Checked half the triangle flange on the header, can't currently see the other half without dropping the turbo. Don't see any areas where I think the gasket has blown out.
- I monitor fuel pressure all the time and it's steady, no drops or erratic behavior
- Innovate shows both closed and open loop AFRs are unchanged
- I did not have time to log idle and closed loop AFRs from UpRev last night but I'll go that just to make sure but last time (pre-sensor replacement) both sensor 1 readings were almost spot on

Questions:
- The obvious one, any ideas on what the issue might be?
- Does the car use this sensor for anything besides closed loop trims?
- The previous questions is based on how concerned should I be about the code if there are no other codes popping up? In open loop (i.e. under acceleration) shouldn't the car use the program defaults my tuner set and not cause any issues?
- One of the possible causes listed with that code is fuel pressure/fuel injectors. Wouldn't I get other codes with it if I had a faulty injector? Also wouldn't the car run a little rough if there were fueling issues?

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