1. Press and hold both buttons and turn on.

2. Wait for about 8 seconds untill “dI” (diagnosis mode) is displayed.

3. Press the select button to change the display to “Co”.

4. Press and hold both buttons to confirm.

5. Press the select button to choose the cylinder C1 or C2.

6. Press and hold both buttons to confirm.

7. Adjust by increasing / decreasing the displayed value.

8. Press and hold both buttons to confirm.

The default is 0 and adjustable from -128 (lean) to +128 (rich).

9. Turn off the key and done.

And this is the video.