The P0455 is an EVAP large leak detected, what the cause is though is hard to say could just be a gas cap or something more
Check all rubber hoses form the engine to the fuel tank.
Code P0455 means "Evaporative Emission System Leak Detected (gross leak/no flow)"
Trouble code P0000 means: No fault found
Leak in EVAP system detected
Evap Leak
That doesn't work on that vehicle.
The check engine code P0455 for a 2002 Dodge Ram 1500 indicates a large evaporative emission system leak. This typically suggests that there is a significant leak in the EVAP system, which could be caused by a loose or damaged gas cap, a cracked or broken EVAP hose, or issues with the EVAP canister. It's essential to address this code promptly, as it can affect fuel efficiency and emissions. A thorough inspection of the EVAP system components is recommended to identify and repair the source of the leak.
EVAP Emission Control System Leak (Large)
Trouble code P0325 means: Knock Sensor 1 Circuit (Bank 1) Trouble code P0455 means: EVAP System Gross Leak (0.080") Detected
TPS volts high. You need to test the throttle postion sensor.
P0455-"A large Evaporative Emission Control System leak has been detected." Usually it means that your gas cap is not on tight, or the seal is old and wont seal tighly. For some reasons, that code comes on for me whan i unplug the AIT sensor even when the engine is off, the code usually goes off within a day however.
P0455 is evaporative emissions system large vapor leak. It has nothing to do with EGR. You could have a loose gas cap, broken vapor hose, or a leak in the fuel tank. Anything that would let gasoline vapors escape could turn the light on.