engine light on for 3yr,no auto problems.What is cost of diagnostic/02sensor on 2005 Hyundai Elantra

what is cost of diagnostic and 02 replacement if needed?
Thanks David

Asked by for the 2005 Hyundai Elantra
1 answer
if you shop around you may be able to get diagnostic for free, try autozone. if no auto problems, than i would not think the sensor needs replacement. it may be tripping due to slight but manageble issues like it may need a tune up, it may need a fuel system clean, etc.
rec. fuel system clean. ethanol treatment to 1 tank of premium fuel. ethanol blend in fuel causes build in fuel system, combustion chambers, exhaust system and causes increased wear to spark plugs. possible build up trippin your sensor.