P0420 check engine light

[Qu8Storm]

I have a 2018 GT with a Roush phase 2 kit installed, only thing done is H pipe. I just had the check engine light pop up on the way to have emissions done come to find out I have a p0420 code. The car has 32,600 miles, has anyone else got this code at such a low mileage? The kit has been on the car for about 20k miles. Could it be the O2 sensor or might it be the cat. Really don't run the car hard maybe once in a while.

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[engineermike]

O2 sensor is possible but most likely it’s a cooked cat. You can verify by logging rear o2 sensor voltage and look for rapid switching.

 

[hossman]

I had P0420 & P0430 codes and they replaced both cats under warranty. There is actually a TSB out from Ford for catalytic converter issues on 2018 and early build 2019 Mustangs.

Make sure you are running the latest calibration from Roush because there were some issues in earlier calibrations that address this issue also.

 

[WildHorse]

Roush car= Ford warranty.

 

[Qu8Storm]

Ok, what do you use to monitor and log your car with? I have nothing at the moment.

O2 sensor is possible but most likely it’s a cooked cat. You can verify by logging rear o2 sensor voltage and look for rapid switching.

 

[engineermike]

Ok, what do you use to monitor and log your car with? I have nothing at the moment.

Vcmscanner. I haven’t used them all but I really like this one.

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