So I bought a cheap ODB2 reader from Amazon:
OUK-BT OBD Scan Tool, Red Universal OBD II Car Diagnostic Scanner Code Reader Automotive Fault Diagnostic Tool for All OBD2 Protocol Compliant Vehicles
for $16 + tax
The device had no problem recognizing the car and reading the error - great $16!.
It read and I cleared a P0440 - which may indeed be due to the gas cap.
Now to see if the error, on my 22 year old baby, returns - which would mean yet another trip to the car doctor (Prevost Motorsport in Bordentown, NJ).
Thanks for the help, guys.
Andrew