California has been requiring diesel vehicle obtain smog certification since 2010. Diesel vehicles which require smog inspections include: all diesel trucks and diesel passenger cars which are 1998 model year or newer, and weight 14,000 GVWR or under. These diesel vehicle must undergo a biennial smog inspection similar to their gasoline counterparts.
The diesel smog check was introduced in order to facilitate smog emission reduction. Please read more information regarding
diesel smog inspection here.
