So i have done everything to get my 2002 subaru outback to pass smog. New Catalytic converters, new o2 sensor, new ECU cars got a tune up. And its still says when i take it in the cat. not ready the monitors arent working.
Replacing parts won’t reset the readiness monitors. The monitors have to reset any time you clear the codes or disconnect the battery and some of them require a specific drive cycle to reset them.
Google drive cycle for your car.