gas cap causing engine lite

If you are sure that the gas cap is the real problem, then yes after 2-3 days the light should go off. Use a new Jaguar gas cap. Also, there are thousands of codes for your Check Engine Light on your Jag, so if the light does not go out, you need to have a Shop scan your computer to see what the real problem is. here is link to an article about Check Engine lights. http://repairpal.com/check-engine-light here are some shops http://repairpal.com/jaguar-repair-in-glendale-heights-illinois