It does flash the code 12, when I do the pin trick, but nothing else, just the 12 code over and over, so I'm not sure what could possibly be the problem besides the egr valve, cause obviously no code comes up, and what do you mean it may be a burnt out bulb? Those can cause the diagnostics to not work? And the check engine light goes on and off, unsure on what that may mean. And by no codes I mean I plug the diagnostic reader in and it doesn't connect to the computer at all
It works properly then, the ECM is not seeing any issues at that time.