Hi all! I have a 2004 Hyundai Elantra that is having problems getting the Cat test to go complete. It is stuck as incomplete and has a pending P0420 code. The code has been pending for the past two weeks, maybe longer as that’s when I first started checking because I wanted to get inspected. This is…

Bad O2 Sensor or Cat Problem?

Tester July 26, 2020, 5:35pm 2

Here’s what the O2 sensor signals should look like.

Tester