That's not an accessory light indicator; hence why Rollerkoaster queried you. The service engine indicator says the engine computer has flagged a problem. You need to get an OBD2 code reader or scantool to find out what the computer is not happy about.
A forum community dedicated to Toyota C-HR owners and enthusiasts. Come join the discussion about performance, towing capacity, modifications, classifieds, reviews, troubleshooting, maintenance, and more!