A quick explanation of CA smog/CARB requirements. Currently CA doesn't have any Smog checks/inspections on Diesels. That's not saying it's not coming. And it depends on where you live on the smog checks for gassers. If you live in a populated area, and own a gasser over 4 years old (by model year) it is required to have a smog check once every 2 years. Depending on certain areas within the populated areas you may have to run your car on a dyno when testing (engine under actual load). However, many areas of CA are not subject to the bi-annual smog checks; they tend to be less populated mountain regions. Every gasser, even under 4 years old, must have a smog check upon sale (this may not apply to vehicles under 7500 mi, I don't remember). That's basically CA smog in a nutshell.