ECU MPG trim? (car lies!)

I have a new to me '15 Golf TDI. It claims to report the instant, since start, since fuel, and extended period fuel economy.


But it lies, by a lot.



For instance, on my last fill it reported 49.4mpg, but the actual "miles driven divided by fuel used" method was 46.7mpg.


Yes, I know you really have to average over several tanks, but I've seen a similar effect over several tanks, so it's not just an under or over fill problem.


Is there a way to trim the in-dash reporting?



VCDS does freakin' everything else, so it seems like there should be a way, but I don't seem to be able to stuff the right stuff into teh goog to find anything.

This may help some, I remember seeing a thread on here or VWVortex walking you through how to do this, but this was the first search that came up. https://idpartsblog.com/2018/03/26/adjusting-displayed-fuel-economy-on-mk7-tdi/

ProfBrown said:

This may help some, I remember seeing a thread on here or VWVortex walking you through how to do this, but this was the first search that came up. https://idpartsblog.com/2018/03/26/adjusting-displayed-fuel-economy-on-mk7-tdi/

Click to expand...

Fantastic!



That's pretty much exactly what I was looking for!


Thanks!


I tried every combination of terms I could think of and didn't come up with that!

For our Alltrack I adjusted the cluster calculation to around 107% and it gives me within .3-.6 gallons (30.4 displayed for the tank now equals about 29.7 hand calculated) which I call good enough as I run larger tires.

740GLE said:

For our Alltrack I adjusted the cluster calculation to around 107% and it gives me within .3-.6 gallons (30.4 displayed for the tank now equals about 29.7 hand calculated) which I call good enough as I run larger tires.

Click to expand...

Yup! 7% seems to be the magic number for me as well.