FT data questions

I have a 2007 v6 4wd, 158k miles. Check engine light is on and i use autolink

$30 al319 code reader, enhanced check and reset engine fault code, live data, freeze frame, CAN car diagnostic scan tools for all OBDII vehicles after 1996, 2025 upgraded

al319 to check the codes, get the P0430 bank 2 code. I saw an old thread on here to look at fuel trim before changing o2 sensor so did that. What am i looking for? longft/shortft live data figures vary around -6 and +1 when idling.

Also i noticed the autolink data had longft1 and longft2 and i watched live data for a few minutes...longft1 was at -6.2 and longft2 was -2.9...should these be closer to the same? shortft1 and shortft2 were about the same.

 

1 is bank one and 2 is bank two, it's normal to see a slight difference bank to bank.
Ideally you should see 0 +/- 10% total (long term + short term) trim on both banks, short term will move alot more than long term but they should stay withing a +/- 10% range for the most part if fuel control is working properly.

The main things to check for when dealing with a P0420/430 before replacing the cat(s) is exhaust leaks upstream or near the downstream O2 sensor as well as verifying proper operation of the AFR and O2 sensors but 90% of the time when you get a P0420/430 the cateyletic converter is no longer functioning properly.