Possible faults which could have caused your Dodge to trigger trouble codes
P0442 and P0455 have to do with the EVAP system. A smog repair station will
need to trace the EVAP leak and determine where the leak is at. Maybe
something as simple as a new clamp or hose (part of the EVAP system) is all
that's needed, or the problem may be more severe requiring the EVAP canister
or purge solenoid be replaced. The first step is to find out where the leak
is at. Note also, EVAP trouble codes have been known to set with faults as
simple as a loose gas cap. If your Dodge truck's check engine light recently
illuminated, you may want to ensure the gas cap is tight and drive your
Dodge for a week or two. If the EVAP code was triggered due to a loose gas
cap, the light will turn off once the computer system realizes no real EVAP
fault/s exist. If tightening the gas cap does not turn off the check engine
light after two weeks, then certainly there is a defect somewhere within the
EVAP system, and a hands on diagnosis will be required.
Although EVAP systems vary they all contain one similar component. This
component is the Charcoal Canister. The canister is responsible for storing
gasoline vapors from the vehicle's fuel tank/s and carburetor float bowl (if
applicable) until the engine is ready to burn them through the combustion
process.
The charcoal canister is usually located in one of the far corners of the
engine compartment. It is normally a black container filled with charcoal
pellets that absorb fuel vapors. Not all charcoal canisters however are
located in the engine compartment. Some vehicles manufactures have mounted
their canisters closer to the vehicle's gas tanks in-order to maximize space
efficiency.
The number one fault which causes vehicle's to fail the EVAP test is broken,
loose or disconnected EVAP fuel lines. It is necessary to trace the entire
EVAP system in order to find the defective section and/or component.