Q: Replaced upper radiator hose and now check engine light is on

The illumination of the check engine light could just be a coincidence, in terms of it happening right after the repair. Once the trouble codes are read and the problem identified, you will know for sure if it is a coincidence. There are hundreds of different diagnostic trouble codes than could potentially cause the check engine light to illuminate. Sometimes the issue is as simple as an EVAP system malfunction such as a loose or defective gas cap. If you request a check engine light diagnostic a certified mechanic from YourMechanic would use a code scanner to retrieve the diagnostic trouble code(s) from your car’s PCM (that is, the specific codes have caused the light to set) and then test the appropriate individual vehicle components or sub-systems (often a sensor, circuit, and the like) to pinpoint the reason why the check engine light has illuminated. If faulty parts or components are identified, such is explained to your satisfaction and the mechanic will let you know of the cost to repair. If you schedule the recommended diagnostic, the mechanic will resolve this promptly for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.