Scotty,
I have a 2019 Hyundai Tucson with 55,000 miles. The check engine light recently came in and my blue driver scan tool showed code P0420 catalyst system efficiency below threshold (bank 1). What does this mean? Also, the air conditioner blows cold on the driver side but seems to be quite a bit warmer on the passenger side. Any thoughts?
You could have an O2 sensor problem giving a false reading on the catalyst. (I wouldn't expect a bad cat on a 2019 model.)
The AC could be low on refrigerant, or if you have dual-zone HVAC the blend door on one side may not be working correctly.
For P0420 and troubleshooting see below: are you out of warranty? (There should be one that also covers emissions components).
https://carkiller.com/scottykilmer/postid/82370/
Both those problems in a 2yr old Hyundai should tell you all you need to know about Hyundai/Kia quality..
Make sure that there is no leak in the exhaust system too.
