VW Golf Onboard Computer MPG Wrong - Fuel Economy Reading Too Low

On my Mk4 VW Golf TDI I've noticed that the fuel economy (MPG) is showing very low on the dashboard as part of the multi-function display of the onboard computer. The dashboard seems to generally be showing around 15MPG lower than the actual fuel consumption.

Initially I thought that there was a problem with the car and that the TDI was using much more fuel than I was expecting. However after a fill up it appears that the MPG fuel consumption is around the expected amount and the onboard display is wrong.

I've not yet worked out where the MPG figure is calculated from but the good news is that the car appears to be returning the expected good miles per gallon that I've seen in previous VW Golf TDI cars.



VW Golf Onboard Computer MPG Wrong - Fuel Economy Reading Too Low