Ive failed the NOX part of the emissions test only. What can I do to fix this?

NoX is controlled by a few different components. The EGR (exhaust gas recirculation) system is primarily responsible. It allows a controlled amount of exhaust to be reintroduced into the combustion chambers at specific times to reduce the cylinder temperatures. The EGR may be bad, plugged up, solenoid or computer may not be commanding it on. There may also be an excessive amount of carbon build up in the cylinders. These problems contribute to engine preignition or pinging which is the cause of NoX. Also, the catalytic converter plays a role. If the catalytic converter is worn it cannot burn the NoX it receives. It does take some specific equipment, information, and training to perform an accurate diagnosis. Call Tobias (480) 488-2914 and we'll help.