[A900ss]

If so, I found this piece of information on another forum that could help:

You could if you wanted use the correction factor in the hidden menu to make the quoted MPG the same as the actual MPG.

here's how:
1. Hold down the odometer reset button and turn the ignition on by pushing start/stop button.
2. Release the odometer reset button, and you should see a menu of 4 items on the dashboard. From here on, use the odo-reset button to advance to the next entry through a short press, and to select through a long press.
3. Choose the one that says Unlock through the above, which will take you to a passkey screen. Your passkey is the sum of the last 5 digits of your VIN. Increment the two-digit number until you get to it, and with the long press of the odo button, select it.
4.then scroll down to correction factor and modify it from 1000 to whatever you require

My car claimed more mpg than it was actually delivering by about 6%. I changed the 1000 to 1060 and it now seems about right.

It did take me a few goes at getting it right , but I much prefer seeing the correct MPG displayed.

If your trip computer reads higher than true figures worked out, make the correction over 1,000. If your trip under reads (very rare!!!), make the correction number under 1,000

[kave]

Great, my computer is constantly wrong. I will try this at once.
I found it in the menus.
Is there something else to do in this menu?

[tnikolov]

Hm, mine reads higher than actually used pretty much all the time. So, the third digit of the 1000 number is actually the percentage off?

[kave]

In the metric world higher consumption is worse. In your world higher reading is better.
For example, my car takes 7L/100km, but the reading is usually 6.5L/100km.
Therefore i set it to 1080, ie 8% too much.
It seems to read more accurately now.

[tnikolov]

Yep, mine reads 11L/100km, but the truth is somewhere around 13L/100km, so I guess I have to make it something like 1150, which should be 15% more, right?