Sensor 1 is the wide band, air/fuel sensor before the cat, aka pre-cat sensor.
Sensor 2 is the narrow band O2 sensor that is after the cat, aka post-cat.
The catalyst test for efficiency compares the air/fuel values to the O2 sensor values.
A healthy cat has the ability to store oxygen, so the sensor 2 lean to rich or rich to lean switching time is slower than the sensor 1 change from lean to rich or rich to lean.
In your case, the rich/lean and lean/rich signals of sensor 1 will be similar that of sensor 2. This means the catalyst is not operating at the required level and a P0420/P0430 is triggered.
I am not aware of any tune that can get a monitor to run and pass. As far as I know, the only way to get the monitor to run is to do the required "drive cycle"... and then it will only "complete" or pass if the test criteria is met.
I can't see that happening without a cat.
What did you do other years to pass emissions?
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