My daughter's 2008 Santa Fe had a bad fuel tank sending unit so she took it to her local dealer and paid $500.00 to have it replaced. Ever since the repairs...

https://www.hyundai-forums.com/threads/santa-fe-multiple-problems.687585/
#6 · Apr 26, 2022

I had a fuel smell in my 2011 previously., especially when filling up or full tank. Found the leak in the connecting pipe between the filler cap and the tank. the hose clamp on the bottom of the flexible rubber hose between the filler cap and the tank was damaged and loose. Its located behind the rear driver tire. Looked like a rock or stick hit it. I remove the rear driver side tire to access. Installed a new hose clamp and corrected the fuel smell problem.

https://www.hyundai-forums.com/threads/2011-santa-fe-p0455-no-obvious-leak.649119/#post-5863985
Funny enough it ended up being the PCM valve, but the biggest culprit wa the fuel tank lock rings and seals. Easy enough replacement and I got to really vacuum under my rear seats! Thank you so much!

Fuel Tank Float Replacement 2007-2009 Hyundai Santa Fe / Fuel Gauge Intermittent?
https://www.youtube.com/watch?v=CIusrFUk4U4

Top 5 Problems Hyundai Santa Fe SUV 2nd Generation 2007-13
https://www.youtube.com/watch?v=bMgRkIkXXCI