Computer monitor reset

If you think "resetting" something is going to help, you can do that by disconnecting the battery for a minute or two. That will cause it to start over with pre-programmed values from the factory, and it will delete any other self-tests that have already been completed. You will have even more tests to wait for.

What you should be after is getting those self tests to run and complete. That is the exact opposite of starting over with the pre-programmed values. Getting those monitors to run requires meeting specific conditions while driving. Those conditions are different for every car model and year. It is often easiest to visit the dealer and have them give you a list of steps needed. Those can include such things as sustained highway-speed driving for as much as thirty miles while never fully-releasing the accelerator pedal, extended period of coasting, brief burst of wide-open-throttle, or holding the accelerator pedal perfectly steady at around forty five mph for at least a minute. If you feel a brief hesitation, or bump from the engine, it is likely one of the self tests is running. You can notice that on some cars.

No. The goal is absolutely to not disconnect the battery. That will erase all the learned data including any diagnostic fault codes. Mechanics rarely resort to doing that. We use scanners to erase fault codes after repairs are completed so any left in memory will not confuse the person working on the next problem months or years later. Using a scanner also does not wipe out the learned fuel trim numbers or any self-tests that have already been completed.

The type of driving required to pass some of the self-tests is very specific in many cases. It is not just a matter of driving around randomly. You should be able to get a list of requirements from any GM dealer. They work on more than just the brand they sell.

GM was Saturns parent company and can give you a list of drive cycle behaviors that you follow to get the monitors to run. As Doc says each of those monitors takes specific inputs for them to run, and some will not run until others have.

Evaporative system: not ready. 1 and 2
Oxygen sensor: not ready. 1 and 2
EGR flow: not ready. 1 and 2

Catalytic converter - not ready. 2

Did you disconnect the battery between the two rejections, When you cleaned the EGR?
Is the CEL light still on?

DTC P0404 is a continuous test. If the light is still on it is likely the cleaning did not work and it is a bad EGR valve. If it is off the EGR may be functioning properly.
A shop with a good scan tool could easily test to see if that is the case as you can command it to various positions and see what the PCM sees as you do that.

Clearing the codes with a scan tool also will clear any set monitor flags and you start over.

The images below are the drive cycles specific to your car. Follow them and it should set them to complete. But do not be surprised if the EVAP does not run, it can be fussy.

Thanks Steve. I am glad I drove old junk that is not quite worn out yet!

On one hand I love my old vehicles, but I do like modern power levels and economy.
HMM a 1957 Chevrolet with an LT4 in it and one of the new eight speed autos with two overdrive gears in it.

http://www.chevrolet.com/performance/crate-engines/lt4-wet-sump

So do you have a current code p0404 that keeps resetting?