I am considering a used V70 T5 2006. When I test drove it the check engine was on. The private seller says that it's related to the emissions system; notably, the pressure in the gas tank. He also says that he is almost certain that the gasket on the gas cap needs to be replaced and the problem will be solved.
I am having it inspected by a mechanic before I buy the car. When my mechanic check the car is it something that he can determine easily? Like the error code? Should I have the seller fix the problem before I have it checked or after. Please advise.
Thank you.