That sounds complicated. I'm not sure those add up to 12 and 55 in my mind! Nephew has the same tester that Auto Zone has.
I took it to Auto Zone. Yep, I think they said EGR. Most of the time the light glows. Sometimes it doesn't. And fuel economy is actually not bad. Helpful Mechanic told me at the time that this code can mean a lot of things and you can spend $100 on a part and still not have it solve the problem. Since Ohio's E-Check is only every 2 years, I've got a while to work it out. Tranny cooler lines, upper radiator hose and transmission fluid changed ... those are my priorities at the moment.
Keep in mind, you're talking to a cheap chick who buys her tires new and skimps on oil changes. Every 3 months maybe, but sure as heck not every 3,000 miles. But I do have ambitious plans to put "a car payment a month" into the bank. At least SOME of that will go into this preventative maintenance stuff. If major things don't happen first, which they always do.