Lexus IS 250-

1.With the car turned OFF, locate and hold down the odometer reset stick on the instrument panel.
2.WITHOUT your foot on the brake, press the engine start button twice while holding down the odometer reset.
3.Now...Your odometer reading will show some dashes that begin to go away one at a time. When the go away you are finished and your next scheduled maintenance has been reset in your IS computer and will alert you again at that time. Hope this helps
Read more: How to reset your oil change light on a Lexus IS250 or IS350 ' eHow.com http://www.ehow.com/how_5210681_reset-oil-change-light-lexus.html#ixzz1ZDyReSum

this light can come on even thought service is not actually due. if the service was performed and the light was not on at the time, sometimes you cannot reset them if they are not actually lit, or 99% of the time the technician forgets if the light was not on. stop by your shop and they can reset it for you in just a few moments, and for no charge. good luck!

Inspect - Brakes, Rotors and brake pads.
Replace smart key battery, coolant,oil and filter.
Reset ( Maint Reqd ) light after oil change, if vehicle equipped with light.
Rotate tire's
Road test - While driving vehicle, check for proper operation of engine, transmission, brakes and steering also check for abnormal noise or vibration from any part of the vehicle.

Check the engine oil level. if low add 1/2 quart and re check untill full. GO get oil change. DO NOT RUN if oil is not showing on the dip stick. The oil weight is in the owners manual.

1. Push the “ODO/TRIP” button to change the display to
blank.
2. Turn the ignition off.
3. Turn the ignition switch to “ON” with the trip meter
“RESET” button held down.
4. Keep pushing the “RESET” button for longer than 5
seconds after the ignition is turned on.
After the above operation, the master warning light comes
on, a warning tone sounds and the message
appears to inform you that the engine oil maintenance data has been reset.

Here's how you reset your oil maintenance light.

To reset the light,
Turn the ignition on
Make sure the odometer displays "ODO"
1.Turn the key off
2.Press and hold down the same button you use to get to "ODO"
3.Turn the key back to ON ( while still holding down the button)
4.Hold the button in until all the flashing lines on the odometer go away and the bunch of "000000" shows up and the maint reset light will turn off.
Your'e done.

If this doesn't work, you would have to try it on "trip A" instead of "ODO".

reset: turn ignition on...push odometer button till it displays mileage on car...not trip milage but actual mileage. Turn car off. Open driver's door, press and hold odometer button....turn ignition to on....hold odometer button for 10 seconds....odometer display will show -----,----,---,--,-,0000000....maintenance lights are reset...lights will come on every 7500 miles to remind you to change oil and check fluids etec....

PRESS AND HOLD IN THE TRIPOMETER RESET BUTTON. WITH IT IN, TURN THE KEY TO THE ON POSITION WITHOUT STARTING THE ENGINE. THE DISPLAY WILL COUNT DOWN IN HASH MARKS FROM 6 TO 0. AFTER IT REACHES 0 RELEASE THE TRIPOMETER RESET, TURN THE KEY TO THE OFF POSITION. ONCE YOU RESTART THE LIGHT SHOULD BE OFF.