P015D code

Light came on for the first time in March, took it to a shop and they said it was the sensor being dirty, so they cleaned it. Everything was good up until last month when it came up again, took it back to the shop and they finally replaced the sensor. Only lasted a couple days before the light came back, and once again went back to the shop where they had it for a while and they said they replaced the oxygen sensor and cleaned the fuel system. I don’t have much knowledge on these things so its probably my fault for not even making an attempt to look into it myself. Anyways, I’ve looked a bit now and since the sensors were replaced, im crossing that out for now, I just went to check for any leaks, but didn’t see any. I also saw that it could be the catalytic converter failing, so not sure where to go from here. Wondering if anyone has any insight on what else to look for, or if I should go to a middle shop to take a closer look?

 

There maybe be a TSB on that issue?

https://static.nhtsa.gov/odi/tsbs/2014/SB-10061281-2273.pdf