DTC P0455 - evaporative system large leak detected.
In order to find the source of the leak, a special smoke machine is used to inject smoke thru the evap system and trace the leak.
There are a couple of common failure areas you can inspect yourself for broken, cracked, or disconnected vacuum lines- check EVAP purge slenoid, EVAP leak detection pump, and the EVAP canister
The EVAP canister is located on the inside of the leftside frame rail just in front of the fuel tank.
If the vacuum hoses are connected and no apparent breaks or cracks in them, an no cracks in the components themselves on inspection, then it will HAVE to have a smoke machine hooked up in order to find the leak
The evaporative emissions leak should not affect being able to make a trip with it