i had my oil changed yesterday and then i got the fuse replaced for my horn. i didnt disconnect my battery when i changed the fuse out, and later is when the check engine light came on. could this have possibly set off the check engine light?? my car was off when i changed the fuse and ive had my oil changed at that place before and hadnt had a problem. i have a 2007 pontiac g5 2 door. i havent had any problems driving my car but it has only been 24 hrs. i want to know if i just need to reset the light or if it could be something more serious. twice the check engine light turned off but later came back on. i cant get the machine hooked up to read what the problem is because one of my car chargers doesnt work so thats out......anyone have any ideas on what the problem could be????