How reliable is the on board fuel mpg readings ?

 

Mine so far... 1200km it was showing real numbers
Why ? do you have any issues?

 

No issues, test drove a new one and was wondering how reliable the readings were.

 

I just filled my new 2010 xls for the first time today. The avg reading I was getting from the vehicle was 11.9l/100km. When I filled up I did the math manually and it came out to 12.1l/100km.

I'd say its pretty bang on, but to be really sure I'd have to compare it over the course of 3 or 4 fill-ups.