1979 model year and older vehicles with original-equipment diesel engines are exempt from Direct Import lab testing requirements. Please note that any vehicle converted to operate on diesel fuel is subject to lab testing requirements if it is a 1968 model year vehicle or newer.
Diesel Smog Check or In Use Check
Diesel Smog Check - Since 2010 California has required all diesel trucks and diesel passenger cars which are 1998 model year or newer, and weight under 14,500 GVW, undergo a biennial smog inspection similar to their gasoline counterparts.
Diesel Smog Test Exemption: The DMV does not require a California emission inspection (smog check) for the following types of vehicles:
- Any diesel car or diesel pickup truck which is 1997 model year or older.
- Any diesel truck which weights over 14,500 GVW.