Error code DF016

[Alex1335]

I have had a check emissions come up on the car today, as well as the service light and engine warning light. I did restart the car twice today after leaving switched off for sometime and the fault hasn’t cleared. The car still starts and drives normally. I have plugged in a diagnostic machine and got the error code DF016 which with a quick search comes up with a broken oxygen sensor which I don’t know much about. Has anyone come up against this error code before and does anyone know how to fix this.

Any advice would be much appreciated, want to fix myself but know very little about cars, especially electrics.