Make sure it has California Emissions on the Window Sticker and emissions sticker under the hood. Also be prepared when registering the vehicle with California DMV to have a smog certificate. Take it to a Ford Dealership locally that does SMOG and ask if their SMOG technician knows how to drive the vehicle to get it to pass SMOG. When I did mine, I took it to a local garage (not a Ford dealership) and it did not pass. I ended up taking it to a Ford dealership. The truck needs to be driven at a speed of 25 mph for a mile or two then stopped with it idling. Have the Ford Technician attach his emissions handheld tester to the OBD II Port while driving. There are 5 tests that the computer will do on the emissions. Once all lights are green, it will pass SMOG. Mine did not pass originally because the computer self-check had not occurred because the truck had not been driven. If you are in SoCal, Orange County, I can tell you which Ford dealership helped me get mine to pass.