How to Turn Off the Check Engine Light in a 2004 Monte Carlo
- 1). Shift the vehicle's transmission into park and turn off the engine. Apply the parking brake, then turn the ignition back to the on position. Do not start the vehicle.
- 2). Connect the scan tool to the Monte Carlo's diagnostic data port underneath the dashboard. Power on the scan tool and select the "PCM" menu. Select the "codes" menu, then choose the option to "clear all codes."
- 3). Power down the scan tool and disconnect it from the vehicle's diagnostic data port.
- 4). Start the engine and verify that the MIL is no longer illuminated.
