Failed smog computer problem?

My car did not pass smog so I took it into the shop. My mechanic says that the catalytic converter is working, that the emissions are fine but that the problem is with my cars computer. Something about a grounding signal and that it is always on even when the car is cool. And that when I am driving and the car speeds up there is a switch that is supposed to be flipped but the computer is not sending the correct signal to flip the switch. I know nothing about cars so I hope I am explaining this right. I took my car back and am going to get a second opinion. If he is correct is it possible/worth it to replace the computer? The car is in great shape. I want to keep it If I can but it has to be able to pass smog (to get my registration (I live in California) Any advise you can give me is appreciated.

More information: smog check results
The error codes are EGR flow insufficient and EVAP Carl incorrect purge flow. Also it fails on OBD system checks. My mechanic says these systems are working but computer is reading it wrong or sending wrong signals. I do not know. The actual emissions results are all good. It says pass in that section.

thank you!