Since replacing your Hyundai Elantra's catalytic converter, the smog check repair station had to reset your Elantra's engine computer in order to erase any trouble codes and reset the check engine light. Anytime a car's ECU is reset its emission monitors (also know as readiness flags) are erased as well. "Emission Monitors" are internal self-tests which the computer conducts to ensure the emission system is working properly. During the smog check "emission monitor" data is sent to the smog machine. If the required emission monitors are not Complete the vehicle will fail the smog check. In order to set the emission monitors a vehicle must be driven an average of 300 miles over the course of at least one week. This is the reason your smog technician has asked that you drive your Hyundai Elantra for 500 miles prior to the smog check.
posted by SmogTips Support
