Truck runs perfectly, has no driveability issues. However, in order to pass smog check here in CA, there must be no codes present and CEL must be off. These 3 codes have been an on again off again problem for many years, even though the truck runs perfect, and has no decrease in mileage. Anyone know what sets these 3 codes and what the possible cause or repair to deal with them permanently is? Thank you in advance.