How do you reset a Mercedes CLK 320 check engine light?

To reset the check engine light on a Mercedes CLK 320, you can use an OBD-II scanner to clear the trouble codes. Connect the scanner to the OBD-II port, typically located under the dashboard, and follow the prompts to delete the codes. Alternatively, you can disconnect the car's battery for about 15 minutes, which will reset the light, but this may also reset other systems. Always ensure the underlying issue is resolved before resetting the light to avoid potential engine damage.