The smog check procedure guidelines require vehicles been smog inspected on 2nd gear, utilizing 1st gear if necessary to achieve the required mph. The smog check machine receives information from the state pertaining specific vehicle testing RPMs and MPHs. In most cases it is not practical to drive a vehicle 15 miles per hour on 1 st gear. Since the ASM smog check program is designed to simulate real world driving conditions it requires vehicles be tested on 2nd gear or if need be 3rd gear (during the 25mph portion).
