Hi Rich,
To change from one measure to the other is as follows.
1. Go to the average fuel consumtion display.
2. Press and hold "Info" button until measure starts to flash. "L/100km or Km/l"
3. Press "Reset" button to change from one to the other.
4. Press "Info" button to return to display.
I do not understand why this is not printed in the manual.
GOOD LUCK Rich.
Regards,
Camwill69