Hyundai Repair: Check Engine, egr solenoid, egr system

Question
after check engine light appeared, I had diagnostics which revealed a bad EGR valve. Replaced the valve but used old gasket(did have part), the check engine light still appears. I have disconnected battery and the light stays off for about 40 miles then comes on again. What else could be wrong & will this prevent me from getting emissions sticker?

Answer
First, you'll want to reread the trouble code to see if it's the same as before.  That way we'll know whether we should continue looking at the EGR system.

Common EGR system problems other than the EGR valve itself include disconnected hoses, a faulty bleed-off valve, or a faulty EGR solenoid.  And there are a couple other possibilities that are less likely.

I don't know where you live, and I'm not familiar with the specific laws in emissions attainment areas outside where I live.  But I think in most cases, a check engine lamp on is an automatic failure.  If they're reading your OBD codes to check emissions, you'll fail.  If they're taking tailpipe readings, you have a shot at passing as long as the lamp is off.