What does code P0455 mean on a GMC and is it safe to drive?
P0455: Evaporative Emission System Leak Detected (Large Leak). Here's what it means on your GMC, what usually causes it, what repairs typically cost, and how safe it is to keep driving.
PowertrainMedium urgency
What this code means
A large leak has been detected in the EVAP system. Could be gas cap left off, disconnected hose, or damaged canister.
Common causes for your GMC
- Gas cap missing or not sealed
- Disconnected or ruptured EVAP hose
- Damaged charcoal canister
- Faulty purge/vent solenoid
Symptoms
- Check Engine Light
- Fuel smell possible
Typical fixes
- Install or replace gas cap
- Inspect and repair EVAP hoses
- Replace canister or valves as needed
Repair cost range
For a GMC, repairs for P0455 often fall between $20 and $500, depending on the cause and whether you use OEM or aftermarket parts. Labor rates vary by location.
Known issues on GMC
GMC P0455 mirrors Chevrolet—gas cap first, then the EVAP vent solenoid near the fuel tank. On Sierra and Yukon, the canister bracket corrodes in northern climates allowing moisture to crack the canister body; physically inspect it before ordering parts.
Most commonly affected models
Sierra 2007–2014Yukon 2007–2014Envoy 2002–2009