I have purchase Passo 2012 Hana yesterday (12 Nov) and replaced its engine oil plus filter today. After that I started driving and ECO light was ON. however, after sometimes, I turned on AC (without turning knob to cool side) and set fan speed to 2. Then after sometimes I turned the knob towards cool side. It worked fine for few minutes after that, ECO light went OFF and "Engine Warning light ( Engine electronic control system malfunction) went ON" and never went OFF even after turning AC off. With this light turn ON and ECO off, I travelled 180 KMs without any problem and reached destination. However, since I am a new user to this car, I dont know how to turn "engine warnig light" OFF. Please help me in this regard. thank you.