In my 09 is250 awd I had setup in the maintenance option to have an oil change in 4k miles. After 2k miles the oil change required light came on. Is that because the cars computer and the manual options to setup your own maintenance are separate? Or does the car have its own sensor to tell you when your oil is actually bad and needs a change?

 

I don't think there is an oil sensor that monitors the oil quality. It's based on schedule.

Mine comes on every 4K miles... I never had to change anything. I have 2 alerts: Oil change coming up and Do your oil change now.

The first one will light up about few hundred miles before oil change is due. Then it's the red light and beep notice to do your oil change now.

 

Mine is come one every 5k but I always change it before it remind me.
Just remember to reset it every time you did oil change. There is a chance that you change your oil before schedule and forgot to reset oil maint. Hope it help!!!
Another reminder store in Nav, don't forget to reset it as well

 

I could be wrong but I think they are two different systems.
-The service/maintenance required indicator on your dash is based on the last reset and should turn ON after 5k miles (for oil change).
- if you have Navigation. There is a Maintenance Screen where you manually enter Maintenance Info for tracking/logging purpose.
Again, I could be wrong since I just got my IS350 recently and the Maintenance screen was blank since the previous owner did not use it.

 

Automatically comes off after 5k miles. You can Goggle how to turn off the light.

 

sounds like to me the light wasnt set back to the interval you wanted thats why it came on again after 2k miles instead of the 5k most people go buy. you can search and there is threads how to adjust that indicatior or just turn it off. the choice is yours