Is it based on the actual condition of the oil, or simply how many miles have been driven since the last reset? In other words, could I put in dirty oil (re-use the same oil), reset the %, and it would start at 100% again?

 

To my knowledge, no system actually reports the oil's condition.

Some cars go purely off mileage, others count revolutions, and some take into account temp and driving habits as well (load the engine is subjected to).

So, yes, if you reset it, even without changing the oil, it will assume new oil and start at 100% again.

No clue what the system in whatever Honda you're discussing goes off of though.

 

Do youre self a favor and ignore that pos maintenance minder . Change the oil at regular intervals and all will be well or follow the minder system and throw the car away at 100k . ......if the engine makes it that far .