I recently had my truck in a shop for an emissions failure. They told me the failure codes but said they didn't have time to fix it. I replaced the evaporative emissions valve on top of the tank and that cleared up two of the three failure codes. The remaining code was P0455 (gross leak). I traced everything and found the hose to the tank from the vapor management valve disconnected. This has a locking connection on it so it was removed on prupose. Does anyone know if that needed to be disconnected for any diagnostic work? Also, would that cause the gross leak failure code? Seems like it would. Thanks.