P0455 Cadillac -i replaced my evap and o2 sensor engine light is still on

Question

When my car sits over night and then i go to start it stalls and then i try again it comes on with no problem what might be the problem

Answer 1

HI there,

With this code it's possible when the car is siting the purge control valve is open. This could allow the fuel vapors into the intake and cause a flooding type of situation. If the purge is open it would create a large evap leak and that's what this code is for.