DIY steps to diagnose check engine light on a 2015 Honda Civic at home

[Alexander18]

The check engine light in my 2015 Honda Civic came on yesterday, and while the car seems to be running normally, I'm worried it could be a sign of a serious issue. I don't have a code reader, and I'm hesitant to just take it to a dealership for what might be a minor sensor problem. For more experienced DIY mechanics, what's a sensible first step for a basic check engine light diagnosis at home, and are there specific common codes for this model and year that I should look into before scheduling a potentially expensive service appointment?

[Mason.H]

DIY plan: 1) pull codes and note them with descriptions; 2) check basics (gas cap, visible vacuum hoses, intake ducting); 3) clear the codes and drive 50–100 miles to see if they come back; 4) research service bulletins for your exact engine; 5) if the same codes return, map out likely culprits and price a repair at a few shops (independent vs dealership).

[OliviaYM]

Would you mind sharing which engine your Civic has (1.8L vs 2.0L or turbo) and your country? With that, I can tailor a precise code list and home-diagnosis steps for your exact model.