Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
I would start by replacing the fuel cap, this is the most common cause of this code. Next in ine with be purve valve, vent solenoid, then fuel tank pressure sensor...But if the fuel cap doesnt take care of it I'd bring it to a shop with a high end scantool so they can monitor system. Let me know if you have questions, thanks.
P0440 EVAP System Malfunction