0420 Code

Hi all,
I had a 0420 (catalytic converter bank 1 ) Code . In fact the check engine light was on for over 2 years or so, but I knew what it was. I changed out the converter this weekend. It was stalling out on me. I thought I was in the clear and it was running great for a bit, but now it is stalling again and the Check Engine came back on. The upper O2 sensor is relatively new , 2 years or so and I did not change it.
You tube is telling me it may be a Mass Air flow sensor or a Throttle position sensor.

Any thoughts are appreciated.
KG

 

Any codes stored now...

 

Stay away from any YouTube that “suggest or tells you change parts”.

To know for sure. You need to graph the upstream and downstream sensors.

If you want to YouTube anything, watch videos on diagnosing P0420/430 codes.

BTW, the chance it being a MAF is very low.

Test, don’t guess.

 

And to add onto the above, use both year make model and OBDII generic when looking at "live" data. Sometimes the data you are looking at is stored/calculated values as opposed to true live data.

 

My P0420 code was from a small leak between the rear CAT and the rear O2 sensor. Once I got it welded up the code went away.

 

Zwatson on to something…….