MPG readout incorrect on dashboard

[Baldrick123]

The mpg readout is way out on the dashboard display of my 2003 c220cdi. It says the car is averaging 63 mpg but it actually does 41mpg. The car has had its ECU fiddled with, could this be causing the bad readout? Greatful for any help. Andy

 

[rf065]

The car has had its ECU fiddled with, could this be causing the bad readout? Greatful for any help. Andy

Do you mean it has been remapped or chipped?

Russ

 

[Ellsy Tanners]

The mpg readout is way out on the dashboard display of my 2003 c220cdi. It says the car is averaging 63 mpg but it actually does 41mpg. The car has had its ECU fiddled with, could this be causing the bad readout? Greatful for any help. Andy

All most certainly.

 

[Baldrick123]

MPG readout incorrect

The car has been remapped for more speed and better fuel consumption by the previous owner. Many thanks for responding. Andy