as a mechanic for over 30 years,it has beenmy great displeasure to have to chase codes.having a code scanner from harbor freightisnt a bad thing however it does no good if you dont understand what actually causes the code to set .your midas should be able to read an historic code,but always ask for a second opinion if they tell you it could be an expensive fix for a code that has reset itself.(probably evap,especially if vehicle was fueled without shutting it off).good luck to you and hope its nothing serious.