What does PO445 code mean on my truck, 2002 dodge ram

DTC P0445 "Evaporative Emission Control (EVAP) System Leak Detected (gross leak)." This is a very common code to pop up--99 times out of 100 it is caused by a loose or bad gas cap. In fact, some late model cars have a "Gas Cap Loose" light that comes on when this code is thrown.

If the gas cap is good and correctly sealed, then an EVAP pressure tester needs to be attached to the EVAP system and the leak found. It could be anywhere in the system so it is difficult to estimate where it is and how much it will cost to repair.

If the gas cap is loose, and you tighten it, the Check Engine Light (CEL) will not go out immediately, but will take some time to go out after the PCM tests the system three times.