List Of 2009 Hyundai Sonata Check Engine Light Gas Cap Ideas. Over the past several months the check engine light has come on at least twice a month, each time it comes on she checks the fuel cap and it is loose, tighten it up an the light shuts off the next day. It should be looked into and fixed, whether it’s a tiny problem, like a lost gas cap, or a more major one, like a damaged spark plug.
It can also be possible that there is an evap system leak or fault even though the check engine light is not on or an evap system leak fault present. A flashing hyundai check engine light indicates a more serious engine problem, and service is required immediately. The second was apparently a loose gas cap, my fault.
