If this is your Maintenance req'd light that tells you when to change your oil, you need to make sure you have the oil changed and the technician should reset it for you. If they didn't, here's the procedure.
To reset MAINT REQD reminder light after engine oil replacement, turn ignition switch to OFF position with odometer reading showing. Turn ignition switch to ON position while holding down ODO/TRIP reset knob. On ES 330 ODO/TRIP reset knob is located to left of odometer display. On IS 300 ODO/TRIP reset knob is located under odometer reading display. On both models, hold ODO/TRIP reset knob down for at least 5 seconds. Odometer should display "000000", and reminder light will turn off. If system fails to reset, reminder light will remain flashing.
〉 Answered on Sep 9th, 2008 by Lori Johnson, Owner and Instructor at Ladies Start Your Engines
The first thing you have to do is find out what is causing the light to turn on. If this light is equivalent to the check engine light then in most states, your vehicle will not pass inspection if you do not find the cause and repair the problem. You will need to take your vehicle to a qualified technician that can scan your car and find out what system the problem is in. From there, most likely they will need to do some tests to find the exact problem. Once they find the problem and repair it, they can clear the codes in your vehicle and the light will go out.
〉 Answered on Sep 9th, 2008 by Suzanne Grego, Technician at City of Philadelphia Fleet Management