How exactly does the maintenance required / oil change reminder light logic work?

Regarding the maintenance required / oil change reminder dash indicator light:

Does it come on at preset, absolute points in time (for example, 6,000, 12,000, 18,000 miles...) OR does it come on 6,000 miles (for example) after it is reset?

Also, on the 2009 1GR-FE, what is the interval, one way or the other?

Thanks.

 

With my 2007, at 4500 miles after I reset it the light flashes for a few seconds after startup. At 5000 miles it stays on until I reset it.

 

It goes by mileage only, there is no "smart" oil monitoring going on, even in the more modern 3rd gens.

 

This ^^

Should be a description in your owners manual as well.

Don't have one? A PDF version is available free on Toyota's website.

 

Same as my 2015.