Originally Posted by JCL

Skip the above article, it refers to the service interval lights (when to do an oil change) and not the service engine soon light (which is a fault indicator).

Using regular gas by itself is not a cause, unless it is really bad, less than 87. Using dirty gas can be a cause.

Make sure the gas cap is tight, a loose gas cap is the most common cause of the SES light. If it doesn't go away by itself in a day or so, take it to the dealer. It can often be a sensor, or something similar, and it is difficult to diagnose without the code reader.

Jeff