1) What is a STAR station?
STAR stations are Smog Check stations that meet higher performance standards established by the Bureau of Automotive Repair. The new STAR Program began January 1, 2013, and replaced the Gold Shield and Test Only programs. If your vehicle registration states your vehicle requires a smog check at a Star Station, you must take your vehicle to a STAR station to be certified. For more information on the STAR program visit

https://www.bar.ca.gov/Consumer/STAR_Program/
2) My DMV renewal notice does not specify that I need to have a smog test at a Star Station, can I still get my vehicle tested at a Star Station anyway?
Yes, you can. Star Stations can certify both Regular and Star Directed vehicles.
3) A family member gave me a car. Is a smog inspection required?
If you acquire a vehicle that is currently registered in California from a spouse, domestic partner, sibling, child, parent, grandparent, or grandchild, you are entitled to an exemption from the smog inspection. Other family members or relations are not exempt and are required to obtain a smog inspection certification.

https://www.dmv.ca.gov/portal/vehicle-registration/smog-inspections/
4) I just had my vehicle smog tested last year, why do I need another test this year?
This occurs if you recently purchased your vehicle and it was in between the regularly scheduled smog test. So let's say the vehicle you purchased is required to be smog tested every other year in December and you bought it in March of that year. You would need to smog it in March to register it in your name and then again in December for the regular Bi-Annual smog. Learn more at https://www.dmv.ca.gov/portal/vehicle-registration/smog-inspections/
5) I have a Diesel powered vehicle where can I have my vehicle tested at?
Look at your renewal notice. If it states at the top of the notice "SMOG Certification Required. Please take this notice to a SMOG check station." Then any SMOG station can test and certify your vehicle.

If the notice states "SMOG Certification Required at a STAR station. Please take this notice to a STAR station." Then ONLY a STAR station can test and certify your vehicle.
6) I have installed aftermarket performance parts on my vehicle, will it pass smog?
Aftermarket performance parts require an Executive Order Number which is issued by the California Air Resources Board to the manufacturer of the part. If the part is CARB approved the manufacturer will include a CARB EO sticker in the box and that sticker must be installed on the vehicle, usually under the hood near the part. If no sticker is found, your vehicle will fail for modified or tampered smog devices. NOTE: just because your part came from a known reputable company doesn't mean it is legal to be installed on your vehicle. It must have a CARB EO# and be approved for your Year, Make and Model Vehicle.

http://www.arb.ca.gov/msprog/aftermkt/devices/amquery.php
7) I am purchasing a used car from a private party, whose responsibility is it to make sure the vehicle passes the smog test?
Section 24007 (b)(2) of the California Vehicle Code states THE SELLER is responsible, it's the LAW. In private party transactions, the seller must provide the buyer with a proof of smog certification prior to the transfer of ownership. If the vehicle is purchased from a dealer, the passing Vehicle Inspection Report should be provided as part of the transfer documents. It is evidence that the vehicle meets state requirements for smog equipment. A vehicle that has not been issued a smog certification cannot be registered. I would recommend that you be present when the vehicle is smog tested. That way you know for sure the vehicle you are buying actually passed the smog test and no other vehicle's exhaust was used to get the passing results.