I have a ‘99 SL1 with 303,000 miles and still with its original EGR valve.

i really have no knowledge about cars, but I know that whenever the SES light occasionally comes on, I remove and clean the EGR, reinstall and then drive around ‘til the computer resets everything to run smoothly again and the SES light eventually goes off. This has been working for me for years and years.

Until recently, when after cleaning and reinstalling the valve, there was no initial rough idling that needed to be corrected. It started up and ran just as it had before the EGR work. And now the light won’t go off.

Did the EGR valve finally die? Is there a way I can easily tell if it’s still operating? Not sure if I should buy a new one as I think I’ve read that there may be problems with aftermarket ones. And there are no Saturns in the local junk yards anymore!

I’d appreciate any of your ideas and suggestions — Thanks!

 

What code?

 

Just came back from Autozone:
P0401, with secondary DTCs P0341 and P0405.

 

So you don't have a cheap scan tool? You can test these without the scan tool but you need to use a dvom to do it. You may want to have a 12V source like another battery or a charger to activate things.
Here's the manual.
https://lemon-manuals.la/Saturn/1999...d%20Diagnosis/