How to prepare your car for a smog test?
How to prepare your car for a smog test? Drive the car for 100 to 200 mi (160 to 320 km) over the course of a week or 2 before the test. The smog test technician will retrieve the diagnostic reports from the car’s computer during the test. 3 Get an oil change if the car needs it. Can a wet tire cause a failed smog test? Wet tires can cause the car to slip off the dynamometer, leading to a false reading and failure. The testing machines will dry your tires, so you can still complete the test on...