How can I tell if I have a faulty Catalytic Convertor or my O2 sensor is bad?

It's very rare that a vehicle will throw these codes and it's not the catalytic converters. A shop will need to plug into the vehicle and watch what the upstream and downstream oxygen sensors are doing. If both upstream and downstream sensors are sending the same signals to the PCM, the catalytic converters are bad. The signal from the downstream oxygen sensors should be a flat line. This is because if the catalytic converters are working there's very little or no oxygen in the exhaust exiting the catalytic converters. When they fail the oxygen levels will be the same or very close to what the upstream oxygen sensors are seeing. Hope that helps! Jim

Thank you

You're welcome. Glad to help! Jim