My dad has a 2002 Chrysler 300M that has a light on in the dashboard that is shaped like an engine. It's not the 'check engine' light, but another light near the lower right hand side of the instrument panel display. The owner's manual says it's on because of a low grade gas or something like that. There are no codes, and the local scan guy says it can't be cleared because it's on because of a sensor, not the ECM. Any ideas on why it's on and how to clear it off?