How do you turn off the Service Engine Soon light on a 2001 Mitsubishi GT?

To turn off the Service Engine Soon light on a 2001 Mitsubishi GT, you first need to address the underlying issue that triggered the light. Use an OBD-II scanner to check for diagnostic trouble codes (DTCs) and fix any problems indicated. Once the issue is resolved, you can reset the light by disconnecting the negative battery terminal for about 15 minutes or by using the scanner's reset function. After reconnecting the battery, the light should be off if no further issues are present.