My wife's dad had the same problem today so I took my vacuum pump and tested the linefrom the charcoal canister (driver side under car in back) to the intake and there was no leak. To make a long story short the electric silonid on the canister was stuck shut, I unstuck it with some air and then used some small jumper wires and tested it with the car battery about six times, put it back together and erased the code from the computer and it has not come ack on yet. Hope this helps you.
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means: EVAP System Small Leak (0.040") Detected
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means: Evaporative emission control system, small leak detected
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)
Trouble code P0442 means: EVAP System Small Leak (0.040") Detected
Trouble code P0442 means:Evaporative emission control system leak detected (Small leak)