I have a 2012 Chevy Avalanche. I changed the passenger side light bulb in the headlight and removed the air filter and the whole case to access that bulb; I followed a YouTube video and was fast and easy. I did not disconnect the battery before doing this. However, the bulb worked well and no check engine light. But the following day my check engine light came on. I took it to Autozone and they did the OBD / free check engine service. She plugged it in to my truck then went back to check on their computer but there was no error codes. She suggested I go and reset the check engine light by disconnecting my battery for 5 minutes then plug back in. I didn’t have the tools so day after taking it to autozone, I took it for an oil change and asked them to disconnect it for that time. They said they would but they only disconnected the positive battery cable and tapped it a few times in the terminal When I left that place, the check engine light was off and I was happy BUT it came right back on after my next stop, a 15 minute drive away from the oil change place. It stayed on as I ran errands, so got home and found my tools. I am a 51 year old lady, a teacher, and I rely on my vehicle, so I disconnected the battery for 5 minutes and when I reconnected it and turned it on, the check engine light was off. But I turned it off and then on…and that check engine light came back on! .. I went back to internet, and found ideas: check gas tank cap is on correctly and yes it is/ turn it on and off 2 to 3 times to reset or clear the check engine light but that didn’t work either. The lady at Autozone said if the 5 min disconnect didn’t work that I could take it back to them so she could plug in the scanner again. So, can you please give me an idea or tell me what I should do next? I was so happy that there was no error code, the lady said that was a good sign and probably I just had triggered the light when i changed the bulb, but how can I get that light to turn off or what do you suggest I do? Please help me because I do not have a good mechanic and am scared to get ripped off or charged a lot for something that maybe I can do. But at the very least I want to be informed and have watched ur videos for years and have followed your advice many many times. I take the truck for regular oil changes and keep it up as best I can. Please help this old teacher, and I have had no other major issues with my truck. Thank you!
AutoZone used to be my go to spot for getting my codes read. But not anymore. I recommend going to another place besides AutoZone. The scanners they use at AutoZone now are weird. They don’t easily give the codes. You have to go back and forth for a print out. It’s dumb.
Try O’Reilly or Advanced Auto.
It’s hard to diagnose the check engine light without the codes. Let us know the codes you get!
I highly doubt changing the bulbs out would cause a check engine light to appear. Probably a coincidence.
Tapping the positive battery cable to the battery was a mistake. People at your oil change place are morons. Find an independent mechanic who knows what they're doing. You'll be glad you did.
Go back over what you did when you changed the headlight, you may have not plugged something all the way in, or fully reseated the intake hose to the box. If the light comes on shortly after you messed with stuff under the hood, it's usually related to whatever you did. Something as simple as vacuum leak can throw the check engine light even though the car runs fine.
