Accuracy of MPG display

[YodaTdi]

I have an '06 1.4tdi & on viewing the mpg display I see figures of 77.5mpg at times (average not current) & wanted to know just how optimistic the cars computer is.

Maybe it is very accurate & I'm very light footed lol  :wonder:

 

 

[Holmesie]

best way to check it is to start at a fuel station brim the tank do a longish journey then end at the fuel station by brimming the tank and calculate the mpg.... you can then compare calculated mpg with your actual mpg

[MattH]

I find mine is quite good. My fuel app reads around 45mpg average over the time ive had the car.

My trip average floats around 38-46mgp. It goes down if I plant my foot. Which is to be expected.

[DGW]

Mine is hopelessly inaccurate with a Trip 2 average of circa 60mpg equating to a genuine 46.3mpg over 53709 miles.

[Turbostream]

Mine is way out. The trip 2 average is showing 68mpg, tank to tank over 6000 miles is 50mpg.

[Big Col]

my trip 2 pretty much aways sits at 62mpg - which (by my calculations) is a real 54mpg.

 

On my trip to work I can often see 75 on the trip 1, but it's lying.

[DanHam]

Mine was on about 65mpg average recently, I was disappointed when I worked it out at just a 52mpg average across a tank full.

It's normally on around 56mpg though with my average being around 47mpg across 6,000 miles.

[booke23]

On my PD100, the trip computer under reads by 6.5%.....so when it says 60mpg on tank average, it has actually done 63.9mpg.

 

On my Octavia 2.0 PD140 the trip computer was over reading by 8.5%....so 50mpg was actually 46mpg. On the Octavia you can correct the computer with VCDS (which I have done) so it's now accurate to within about 1%.....unfortunately you can't correct the trip computer on the Fabia.

 

It seems rare to find a trip computer that is actually reading correctly......they either over read or under read to some degree.

[Kyle_vrs]

Mine normally under reads by about 2mpg. I usually get 55mpg over a tank doing between 550-600 miles yet the trip 2 shows around 53mpg

[vRS Joe]

From my experience it reads about +30%

[sheldon_cz]

I don't have a Fabia, but I have an Octavia from the same era. My HUD sits well with my fill-up calculations. On long journeys, the average shows 50 MPG, and on short ones (not so frequent), it goes down to 25-ish. The result can be found in my signature.

[@Lee]

I've never been bothered enough to check, when it's empty, I go to the garage

[XLBaconDoubleCheese]

Mine is spot on!

[wilsy7]

Mines calculates about 2 mpg under actual value.

[DanHam]

Seems to he quite hit and miss then! Am I right in thinking it can be adjusted with VCDS?

[Harry1212]

Is the display that shows how many miles you have done accurate then or not??

[DanHam]

Is the display that shows how many miles you have done accurate then or not??

That one is accurate as it reads the same as the digital one on the speedo. I've tested that

[booke23]

Am I right in thinking it can be adjusted with VCDS?

 

No, not on the Fabia anyway. 

 

It is possible on the Octavia though.