5.7 vortec o2 sensor question Torque app

[highcascade3]

So I have the torque app, and was looking at my results and found this message:

"Closed loop, using 1 O2 sensor (feedback fault)"

Seems simple enough, but when I look at the O2 sensor data, both are reporting and both oscillate as one would expect on the graph. I unplugged each one at a time, and both times it would not come out of open loop.


Any ideas or similar experience? I know this is a knowledgeable crowd.

 

[mazdamonky]

It could have been an intermittent code. Sometimes a code gets thrown just long enough the ECU realizes it and then it goes away. This happens with my O2 sensors pretty often. If i pull up intermittent codes it shows a bad Cat, however the check engine light never comes on. I believe this is mostly because my cat is 15 years old and just worn out.

 

[highcascade3]

It doesn't ever trigger the CEL or show up in pending codes, and it has been just using the 1 sensor in closed loop for several hundred miles (likely far more, but that's how long i've been monitoring)

I have higher LT fuel trims,(but not at idle, where I have a miss when it is hot outside).

I replaced o2 sensors about a year ago, but clearly I have something going on...

 

[Pontual]

Wiring is fine? Ecm ground? Check between ecm pin and sensor.