CEL - 118602 - Help Diagnosing Please!
 

Good Evening,

A well kept 2014 BMW X3, with the N20 Engine (2.0L) recently threw this code " 118602 Oxygen sensor before catalytic converter, mixture control: Exhaust gas after catalytic converter too lean"

About 10k miles ago we replaced the Pre-Cat O2 sensor, but really have not had any issues or check engine lights since. The vehicle currently has 105k miles on it, and I am worried this could be the CAT going bad. I found the attached technical article, but am unsure of exactly how it wants me to test the items. I did hook up a Foxwell computer that let me graph both O2 sensors, nothing particularly jumped out at me,

Current next step - Reset the CEL, see what type of interval it is taking to re-appear, and I will write back. I will also do a deep visual and look for any leaks, issues etc.

Any thoughts?