2003 Huyndai Accent won't pass smog?

Asked by Sep 05, 2012 at 05:49 PM about the 2003 Hyundai Accent GL

Question type: Maintenance & Repair

I have a 2003 Hyundai Accent that recently did not pass smog (CA). mechanic suggested new spark plugs, repaired, came back, no luck. High NOX?  Anyhow, he stated that is was the catalytic converter, but that there is no aftermarket part, only dealer part. When I call the dealer to inquire about part purchase, they ask if the check engine light was on to indicate catalytic converter, otherwise, they say I should get a 2nd opinion since the part is non-refundable and installing it won't guarantee that the car will pass smog. Any other ideas as to what is causing the high NOX (?) value, I was told that an oxygen sensor alone won't help and we would probably need to replace that along with the catalytic converter.. Any suggestions? One small detail: my daughter accidentally put 1/2 gallon of diesel into her car 8 months ago (ran out of gas, went into dads garage and filled from gas container that she didn't realize was not gas) , it bogged and smoked like a dog until it was out, but no other apparent mechanical issues. we did change the spark plugs and fuel filter after that..Any suggestions?

2 Answers


i am an emissions inspector in connecticut, a 2003 car doesnt have to run on the dyno so the nox gas has nothing to do with you failing emissions. the reason you are failing as far as CT is concerned is because of the check engine light and whatever those codes are. get those fixed and you will pass

1 of 1 people found this helpful.

Have the EGR system inspected. For leaks a stuck open valve or large Carbon build, if it is cleaned out by your shop. Run a fuel system treatment. I stand by techron intake system cleaner, run your tank down to E add in Cleaner( after any service) and fill with plus or super fuel. Run the tank back Down on E to complete treatment. I've seen cars here in Massachusetts fail box for something as simple as cleaning the throttle body.

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