does anyone know how i can test to make sure the egr valve is working? if i don't have a CEL, does that mean that the egr valve must be working?

i had a smog test and everything passed very easily, but my NO measurements were way past gross polluter. this is supposedly caused by issues with the egr and high combustion chamber temps. i took off the valve and the path was dirty but nothing super clogged.

should i run a bottle brush up the path as far as a can to the IM? i don't want to replace my egr valve if i don't have to, i just don't know how to test if it's operating the way it's supposed to

 

Find the wire diagram and determine what wires are the power and ground, remove EGR valve(if not already) and apply 12 volts to the power terminal on the EGR valve. If it opens when powered and closes when u remove it then it's working but if you don't have a any codes for EGR then I would say it's working fine. It doesn't hurt to do a port cleaning and a fuel induction service(cleans the carbon build up off the valves and top of pistons)

 

If you don't have a CEL i would assume your sensor is going bad or your EGR is fine. My EGR valve went bad 2 days ago (carbon stuck in it), it threw a CEL and gave me some idling problem (RPMS hovering over 500).