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Q: I have failed smog 2 times this past year (2016) for high NOx at low speeds but passed at higher speeds.

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But the codes in the ECM read nothing about the catalytic converter, only the vehicle speed sensor (p0500), which I already replaced and code p1447 . What is the possible cause of this? There is a strong odor of fuel vapors coming from the car and the exhaust smells bad. What other problems could cause this? Ive also had code p0600 as well. I cleared the codes and the check engine light has yet to come back on, but when I plug the scanner into the car, it has the p0600 and p1447 code. The check engine light works.

My car has 186500 miles.
My car has an automatic transmission.

Hi there. The issue that you are having is the purge valve on the fuel system is not functioning correctly and needs check and possibly replaced. The code P0600 is referring that the dash is not communicating to the ECM (computer). Check the wiring harness to the computer from the dash and see if anything is loose or damaged. If you need further assistance with your emission, then seek out a professional, such as one from Your Mechanic, to help you.

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