On the california car there is a LED blink light on the diagnostic connector. Turn key on, push button for 3 seconds and the first code can be read. The number of blinks is for 1 (each) code. To erase that code after counting, press the same button & count slowly to 8, and that has to happen with-in 10 seconds of the last blink. Then see if there are any other codes by following the same sequence. When the light blinks only once after the 3(three) sec. push; there are no more codes! There is an emission problem w/car, most likely no problem with driving!!