Chevrolet 2004 Monte Carlo Owner's Manual page 279

After changing the engine oil, the system must be reset.
To reset the CHANGE ENGINE OIL message use
one of the following procedures:
Using the Radio
1. Turn the ignition to ACC or ON, with the radio off.
2. Press and hold the TUNE DISP knob on the
radio for at least five seconds until SETTINGS
is displayed.
3. Press the SEEK PSCAN up or down arrow to scroll
through the main menu.
4. Scroll until OIL LIFE appears on the display.
5. Press the 1 PREV or 2 NEXT buttons to enter the
submenu. RESET will be displayed.
6. Press the TUNE DISP knob to reset. A chime will
be heard to verify the new setting and DONE will
be displayed for one second.
7. Once the indicator has been reset, scroll until
EXIT appears on the display.
8. Press the TUNE DISP knob to exit programming.
A chime will be heard to verify the exit.
9. Turn the key to OFF.
If the CHANGE ENGINE OIL message comes back on
when you start your vehicle, the engine oil life system
has not reset. Repeat the procedure.
Using the Accelerator Pedal
1. Turn the ignition to ON, with the engine off.
2. Fully press and release the accelerator pedal slowly
three times within five seconds. If the CHANGE
ENGINE OIL message flashes, the system is reset.
However, if it stays on, it did not reset. Repeat
the procedure.
3. Turn the key to OFF.
If the CHANGE ENGINE OIL message comes back on
when you start your vehicle, the engine oil life system
has not reset. Repeat the procedure.
5-23