My 2004 MCS JCW has the navigation system which is where the fuel economy is displayed. The fuel economy displayed is quite inaccurate and I understand that accuracy is controlled by using the appropriate correction factor. I have stepped through the ECU menu attempting to get to section 20.0 to set a new correction factor but it just skips over 20. I assume that this is because I have the navigation system. Is there a way to set the fuel consumption correction factor on a 2004 R53 with the navigation system? Or is it not possible to set a correction factor on a 2004?

 

I think it's possible....but you have to use some special coding software to do it. If you search the forums, you should be able to find a few threads on it. Mine constantly reads around 2mpg higher than I'm actually getting....I think that's a common issue. Not sure if you can ever get it 100% accurate....even with adjusting it.

 

Mine is way off. Showing 29 to 30 MPG when I'm in the low to mid 20s based on trip odometer miles divided by gallons taken on at fill up. Suggests that the correction factor needs adjustment but can't figure out how to do it because my ECU menu skips over section 20.

 

mine is actually accurate to the .2 >.<

 

If you are getting low 20s on the highway.......something is wrong.

 

Its mostly city type driving, not highway, with a heavy foot on the pedal.

 

Ok, that makes more sense

 

Does anyone know how to get a correction factor into the ECU when you have a navigation system? Mine is still reading quite high even after an ECU reset. Last tank fill up I calculated about 23 MPG around town and the display on the NAV system is showing about 28 MPG.