Hello! The check engine light in my 2012 Mazda 3 has been on for nearly a year.
I’ve replaced both oxygen sensors, the air intake boot, gas cap, and the mass air flow sensor.
What else could be wrong with it? It’s code p013A (manufacturers control)
thank you!

 

Welcome to the forum

Lesson learned is DO NOT RANDOMLY REPLACE PARTS that have not been tested as the fault.
Unfortunately now you get to start all over again and test each part you replaced and specifically the HO2s run a data log of them from a complete cold start through to warm up. .