If you mean the oil light:
Chevrolet Impala, Monte Carlo, 2000-05
Turn the ignition to ON without starting the engine. Fully press and release the accelerator pedal three times within five seconds. If the CHG OIL SOON light flashes two times, the system is resetting. Turn the key to OFF, then start the vehicle. If the CHG OIL SOON light comes back on, the system has not reset, repeat the procedure. Follow this procedure to reset the GM Oil Life System using the DE 100 Series Radio®. Turn the ignition to ACC or ON and the radio off. Press and hold the DISP button on the radio for at least five seconds until SETTINGS is displayed. Press the SEEK up or down arrow to scroll through the main menu. Scroll until OIL LIFE appears on the display. Press the PREV or NEXT button to enter the submenu. RESET will be displayed. Press the DISP button to reset. A chime will be heard to verify the new setting and DONE will be displayed for one second. Once the message has been reset, scroll until EXIT appears on the display. Press the DISP button to exit programming. A chime will be heard to verify the exit.
Otherwise is there a scan code for it?