Ive had my 2003 hyundai sonata LX V6 for 4 months now that will not pass smog i have already received my 30 day permit and three 10 day permits i have took it to 3 different mechanics that cant seem to figure it out, there are no Check engine lights on, i have changed out my Throttle Position sensor,completed the drive cycle after that, my car Drives great no delays or problems but still keeps getting rejected at the smog check, the areas of reject are OBD fuel, OBD catalyst & OXY sensor, the mechanics say my sensors are good my gas cap is good and there are no known problems,my last resort would be to take it to the hyundai dealership,can anyone help me out?


Asked by Mar 12, 2015 at 06:31 PM about the 2003 Hyundai Sonata LX

Question type: Maintenance & Repair

2 Answers


Some vehicles won't run emission test unless the fuel level is at a certain point, if you fill the gas tank and then run it until it gets below 1/4 tank it should have run all monitors. Also, how many miles have you driven and do these mechanics reset the monitors each time they check it out?

Best Answer
William Kyle

car may have a bad piston ring and burning oil and making it not pass emission check if lite blue smoke come out tale pipe when pushing on the gas if lite blue smoke comes out might be rings or oil problem. i had almost the same problem found out the engine was burning oil i had 2 bad piston rings i had pistons and piston rings replaced and the problem went away. no saying that's the problem just had the same problem or engine may have a internal oil leak were to much oil is mixing with the gas.

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