When a Check Engine light illuminates on your dash, unless there's an immediate and noticeable change in the way the car performs, Don't Panic. The emissions system is detecting a fault in the system which stores a code in the vehicle computer for the technician to read and decipher. This light may come on and turn off, come on and stay on or flash. If it flashes, it's a more urgent message to have it checked. If not, get it in to AutoAid as soon as practical. Some check engine lights may cause the vehicle to stall, mis-shift lose power while others may have no noticeable effect. Best practices: Have it checked for your peace of mind