Computer codes help

[JCinFW328i]

Where could I find the descriptions of the codes: P0441 and P1478? My check engine light came on and thse ar ethe codes that the Pep Boys guy gave me. Thanks!

 

[Kirby]

P0441 Evaporative Emission Control System Incorrect Purge flow
P1478 Evaporataive Emission System Leak Detected

My guess is that your gas cap was loose. Do these codes keep coming back or was this a one timer?