Hi,
Does anyone know how accurate the fuel computers are on the 406 HDi's,I decided to do a bit of an economy run the other day on a trip from Bedfordshire to Surrey,I took it pretty steady and rarely went over 2000 rpm in 5th gear and took my foot off the gas downhill etc,on the return journey i did the same and got an average of 64.7mpg which is pretty impressive i thought.Without sitting down and actually working it all out could i rely on the readings,Mark.
Fuel economy/average MPG
Moderator: Moderators
- Doggy
- Mod with a 2.2 HDi, De-Fapped!
- Posts: 10710
- Joined: Mon Oct 13, 2008 11:49 pm
- Location: Northants
Re: Fuel economy/average MPG
Hi Mark & welcome to the forum.
Most people reckon they're pretty accurate - I've never found mine to be out by anything significant when I've checked. (But I've never got near 60 mpg).

Most people reckon they're pretty accurate - I've never found mine to be out by anything significant when I've checked. (But I've never got near 60 mpg).
2002 HDi 2.2 Exec Estate, (2008-12) (wonderful)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
2003 HDi 2.2 6-speed Exec Estate (2012-19) (also a gem)
2009 Citroen C5 2.0 HDi VTR+ Estate (godawful heap)
2008 BMW E91 330i touring (great fun - murdered by a reversing SUV)
2007 BMW E91 325i touring (slower smoother quieter)
Re: Fuel economy/average MPG
Thanks for the reply,I'll have to work it out and see but nice to know they are fairly accurate.I've never really tried the economy before but driving like this for a change seems to pay off 

- Welly
- The moderator formally known as Welton
- Posts: 15033
- Joined: Tue Jan 10, 2006 12:52 pm
- Location: East Midlandfordshire
Re: Fuel economy/average MPG
Yes they are pretty accurate. If you can take the boredom and follow lorries on the Motorway at 60 mph then you can achieve amazing MPG's, you'll be late but save a fortune
Tyre pressures make a big difference too.

Tyre pressures make a big difference too.
Cars in my care:
2021 Kia Spottage 1.6 Pez Turbo Dual Clutch Gearbox Trickery
2013 Renner Twingo - donkey work
2021 Kia Spottage 1.6 Pez Turbo Dual Clutch Gearbox Trickery
2013 Renner Twingo - donkey work