2024 Sierra Denali Evap Leak. Again, replaced with a gm genuine, accept this time my beloved check engine light did not come back on after three days. The p0455 diagnostic trouble code appears when there’s a leak in the evaporative emission control (evap) system, and the system can’t maintain pressure.

You may be wondering, how do i fix trouble code p0455? If you see a p0442 dtc, you know there is a fuel vapor leak.