How do you reset check engine light 2005 Volvo s40?

To reset the check engine light on a 2005 Volvo S40, you can use an OBD-II scanner to read and clear the trouble codes. Alternatively, you can disconnect the car battery for about 10-15 minutes, which will reset the system. After reconnecting the battery, the check engine light should turn off if the underlying issue has been resolved. However, it's important to address any underlying problems that triggered the light before resetting it.