How to prepare your vehicle for smog test and how to avoid your vehicle from failing for little problems ?
Drive your vehicle 15 to 20 minutes before you arrive to smog station.
Make sure your vehicle oil is changed.
Make sure your vehicle tires are evenly inflated.
Make sure your check engine light are not on always.
Make sure your vehicle battery was not weak.
Make sure you drove your vehicle at least 50 miles after you changed the battery or made any repair to your vehicle.
Make sure your gas cap are not cracked and secured.
Make sure your vehicle are clean because clean vehicle give a technician idea that the owner is taking care for his /her vehicle.
Advice:
Better to have your vehicle smogged in Smog Star Test only station, which is not allowed to do any repair.
Smog star test and repair station are depending on the repair. There smog test price normally cheap. (Why??!!!!)
Watch for some (not all) smog & repair stations trying to sell you unnecessary repairs, or fail your vehicle so they can sell you some repair in order to pass your vehicle smog test.