Engine code po455 - 2004 Chevrolet Silverado 1500 Crew Cab

Check this info about P0455 - Evaporative Emission Control System Leak Detected (no purge flow or large leak)

This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. It means a large leak has been detected. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

Symptoms: You likely won't notice any drivability problems.

Causes: A code p0455 most likely means one or more of the following has happened:
A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
Other leak or damaged piece in EVAP system

Possible Solutions: With a p0455, the most common repair is to:
Remove and reinstall the gas cap, clear the codes, and drive for a day and see if the codes come back.
Otherwise, replace the gas cap, and/or
Inspect the EVAP system for cuts/holes in tubes/hoses (you may hear a vacuum noise or smell fuel), repair if necessary


Check it and keep us updated.

Loose gas cap or bad cap.Tighten gas cap then reset computer and wait to see if code comes back.