Why did my engine light come on after replacing battery?

Thank you! I did your trick twice for at least 5 secs with my Kia Sportage 2011 and the engine light is now off (after replacing the battery).

This trick worked perfectly for my 2008 Mazda 3 gt . After charging my drained batt. ( left dome lt on , oops ) the C.E. light came on and stayed on. Did the 5 sec trick , C.E. light is gone and am good to go … Thank you for posting Lasagna14 , Unsatble,JA,falfa and Repair PAL !!!!!! UPDATE 5/19/2019... my check engine light came on 9 months later.I recalled I had filled the tank the day b4.gas cap was loose,was99.9%sure it was the cause for the light( just has a full tuneup last month),Tightened gas cap ,reverse engineered trick (took neg. cable off battery for 15 minutes pressed horn, turned lights to on to drain any stored charge) reattached neg cable , then did the trick for 5 sec and payed homage to gremlin lordes, started engine ,NO LIGHT ! some would say disconnect both cables for safety ,am to lazy lol .had to reset clock and radio presets ,good to go ! thanks again unstable Ja ! tags : 2008 Mazda 3 check engine light new battery loose gas cap reset clear how to for those on google search

THANK YOU. I saw your answer and just did this to my Mazda 3 after it completely died needing a new battery and the check engine light came on. I turned it to the on position for 10 seconds, did it twice. Light went off. The auto shop I took it to wanted a lot of $$$ just to diagnose the light....who knows what they would have tried to charge me after that.

excellent ! all thanks to unstable JA !

Installed new battery in my Rondo this morning and it did the same thing. Unfortunately, your trick didn't work for me. I tried it four times, still no joy.

Thanks for the advice. Planning on getting the code checked and will provide any info. that I get. Hope is that it is something simple like a fuse fail and nothing major. Was hoping that perhaps someone had the same situation happen: new battery install=engine light

Many possibilities, one situation may not be relevant to another!

Mechanic recommended to wait a day or two to see if light goes out on its own as there were no issues pre-existing battery change. Low and behold, light went out on its own. Still curious as to what might have caused it to come on in the first place but much relieved that it went out. 'The light of doom' is gone for now.

We had the same problem. Changed battery and then the check engine light came on. Got a code P0106. Checked under the hood and everything looked ok. Light ended up going off on its own a couple of days later.