21-01-035H

Certain 2011 2015 Sonata Hybrid vehicles (YF HEV) may experience check engine light illumination with Evaporative System (EVAP) leakage related DTC P0442 Small Leak, P0455 Large Leak or P0456 Very Small Leak stored. These conditions primarily occur in the California coastal areas that are subject to marine layer cloud cover. Salt particulate deposit can form inside the Natural Vacuum Leak Detection (NVLD) sensor which may cause intermittent operation prompting the DTC P0442, P0455 or P0456 and check engine light illumination. This bulletin provides the procedure to install a new Air Filter Kit with an updated filter to help prevent entry of the salt particulates. In addition, replace NVLD sensor if DTC P0442, P0455 or P0456 is stored in the Engine Control Module (ECM).