MPG Computer Errors
Thread Starter
Junior Member
Joined: Jun 2016
Posts: 25
Likes: 8
GLC300
MPG Computer Errors
I have a US spec GLC300 and run premium with up to 10% ethonal. I have 10,000 miles on the car now and the computer shows higher mpg than calculated using miles driven and fuel added. The error over 10,000 miles is close to 2.5 mpg low (about 29mpg calculated on board and 26.5 calculated at the pump).
The BMWs and Volvos I've had were at most .5 mpg off. Anyone else notice the inaccuracies of the on board mpg calculation? Can the dealer calibrate this?
The cynic in me says this may be on purpose since most people do not check what the car displays with the actual mpg calculated the old fashioned way.
The BMWs and Volvos I've had were at most .5 mpg off. Anyone else notice the inaccuracies of the on board mpg calculation? Can the dealer calibrate this?
The cynic in me says this may be on purpose since most people do not check what the car displays with the actual mpg calculated the old fashioned way.
Super Member
Joined: Jan 2014
Posts: 761
Likes: 90
From: right to be forgotten
right to be forgotten
I've never seen an obc that matches manual calculation on any of the cars I've owned. However I've also never been able to establish whether it is due to errors in the manual calculation or in the obc. I just use either method as a relative measure and not a comparative one.
