Yes. If you have not reset the ECU when you have replaced them, the cel will still remain. Just take off the negitive terminal of your battery for 20 seconds and your good.

If you did this and the cel came on again, you might have damaged it during install. They are pretty delicate.

Yeah, a orignal, clogged EGR valve is not unheard of at 180k. Clean it and reset the ecu as noted above.