hi all

can anyone help plz. the speedo on my 52 octavia vrs is under reading [standard size tyres etc], at 30 on the clock road speed is approx 32mph...the difference increases with speed, at 60mph [clock] my actual road speed is approx 69mph. this is reduces the clocked mileage on the odeometer also..has anyone any suggestions.

regards les

The speedo is electronic and gets its signal from an electronic sender unit, I guess the sender unit has gone faulty and sending too many pulses so everything over reads. It is possible to display current road speed in km/h on the climatronic unit. A guide on how to access this is on my website.

http://pub26.bravenet.com/faq/show.php?usernum=2167829440&catid=3555

This is not just standard to all cars but also a legal requirement.

I wouldn't worry about the effect on mileage, all other cars suffer in exactly the same way so it won't count against you.

Update - Sorry - I misread your post, never heard of one under-reading before.

checked it on the climatronic and it matched speedo.well folks what is it more likely to be then...a faulty sender unit [fingers crossed] I am presuming this as the climatronic was the same as the dash therfore in my ignorance I believe that the signal from the sender may well be incorrect. has anyone any ideas as to the price for a replacement and labour.

I'd guess the instrument cluster must have different options (set from VAGCOM etc.) to allow for different wheel size fitting. If you haven't a fault as such, perhaps yours is set wrong for some reason and one of the other options might give a more accurate reading?