Not,
What year is your car?? S13 or S14??
On S13's there are two soleniods hidden behind the engine & close to the O2 sensor which regulate & control the BPT & EGR valve. If these soleniods get clogged / dirty or fail, they won't allow hot exhaust gases to flow back into your combustion chamber thru the EGR Valve. The hot combustion gasses that flow back into your combustion chamber are used to regulate the formation of NOX gasses in your exhaust. Click on the attached link for a better explanation.
Mopar Magazine | Reducing NOx-ious Emissions
Anyhow, hope this explanation helps you to understand how NOX gasses are formed. Good luck with finding & fixing the problem in your EGR system.
Hope this helps...
ID