why won't my check engine turn off?

P0403 is telling us there's a problem with the EGR vacuum control solenoid or the wiring going to the solenoid. There's a short or open condition in the circuit. Carefully inspect the wiring going to the solenoid and the electrical connection at the solenoid. Look for breaks, damage, or corrosion that will cause a bad connection. If all this checks out good, replace the solenoid. Once you clear the computer, after the repair, drive a few days with the gas gauge between three quarters and one quarter full so the computer will run the diagnostics on the EGR system and set the readiness monitors for smog inspection. Hope that helps! Jim