[aedocw]

That o2 sensor is an important part of the engine/emissions management system. Without that info, the car computer is not able to efficiently map the fuel/air mixture and over time is likely to lead to more problems. Depending on the car, the CPS sensor could be really critical (like if you've got variable valve timing in an interference engine I think?). Understandable you want to ignore that check engine light but recognize that $600 cost to repair could balloon into a lot more (even a destroyed engine).