Before you can register a car, truck, motorcycle, or motor home brought in from Mexico into California (United States), you must be able to prove that an entry was filed with the U.S. Customs and Border Protection (CBP).
The Department of Motor Vehicles (DMV) will not register a vehicle that has been imported into the U.S. without proof that an entry was filed with CBP and proof the vehicle conforms to U.S. emissions and safety standards; this is where the smog check comes in. Your vehicle from Mexico will need a California smog inspection in order to be eligible for import and California registration. If your vehicle does not conform to U.S. emissions or safety standards, you will not be able to register it in California (or the US for that matter). Your options will be to either bring the vehicle up to U.S. standards or export the vehicle.
If you drove this car into California, you should have declared the vehicle for import at the border and the entry paperwork would have been handled there. If you failed the declare it at that time you may do so now by contacting a local port. They can provide you the proper documentation.
When filing an entry with CBP for your vehicle, you must be able to demonstrate to CBP that you own the vehicle and it conforms to U.S. emissions and safety standards. You have to submit proof of ownership such as a certificate of title, bill of sale, or manufacturer statement of origin to a CBP Officer at the port.
Additional forms needed for importing a vehicle from Mexico is the Department of Transportation (DOT)Form HS-7, and Environmental Protection Agency (EPA) Form 3520-1. The California DMV will require these forms when you attempt to register your vehicle from Mexico.
Once you have filed your entry and paid the import fees for your vehicle, which is 2.5% for cars and 1.9% to 2.9% for motorcycles, you will receive the CBP Form 7501 Entry Summary. This form is your proof that you filed your entry with CBP. Be sure to keep a copy to present to the DMV when registering your vehicle.
