On a road trip, I accidentlly pumped a tankfull of ethanol added gasoline(really had no choice anyway out in the middle of nowhere on empty). The maintainance light came on and stayed on for 2-3 hours and then finally went out.
You may have pumped some ethanol, or you may have pumped some low grade or contaminated gasoline.
I'd chalk it up to the latter since your presently having no problems I assume.

 

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Your maintenance light comes on for NO OTHER REASON than a particular mileage has been reached since it was last reset. it would NEVER come on for ANY other reason.



i think you are confusing this with your Check Engine light, which more than likely did come on because of the fact that you used a gasoline in an engine that was nowhere near designed for it. unfortunately for you, there is a good chance you have drastically shortened the lifespan of your engine from such an act. why you would do this i have no idea. E85 eats away at the internal gaskets/components on the inside of your engine. it was also probably causing some severe knock/ping/detonation, etc, which is why you were getting a check engine light. but seriously, you probably did some damage.