MY12 Passat Wagon - Inaccurate Speedo and variation between digital & needle speedo

[JBlyth]

I have just taken delivery of my MY12 Pass Wagon TDI and I notice that the speedo readings are less than accurate.

When my GPS (I checked with two) shows 100kph, the digital speedo shows 103kph and the analogue needle 105-106.

I had hoped the VW would be much more accurate. One of my pet peeves with a series of Subaru's was that the speedos always significantly overread - although I noted when in Japan that they are spot on!

Is there so option in the maintenance setup commands to at least adjust the speedo needle to match the digital readout?

Many thanks
John in Sunny Carnarvon - WA

[dylan8]

they are all like that sadly... dads CC and my bora are the same.
i can understand the speedo being down compared to your GPS. but the digital and analogue needle being different to each other would really get to me

[Riker]

Nothing unusual there i'm afraid JBlyth.... I have had similar occurances in a V6 Vectra, Jetta 147 TSi & Honda Accord Euro.

Agreed however that the cars analogue & digital readouts being visibly different would p*** me off..

[JBlyth]

As a matter of interest, and after reading the manual more extensively, I raised the tire pressures from the Dealer's recommendation of 36psi to the vW recommended 39-43psi (actually 42 front and 43 back seemed a good approximation for 2.7 - 2.9 and 3.0 bar).

Now the digital and analogue speedo's are almost identical, so I guess this implies that one is devolved from final drive speed and the other from wheel rotation diameters - at a wild guess....

Cheers
John in Sunny Carnarvon - WA

[WestOiler125]

Glad that fixed it, and you would have noticed the need to recalibrate the tyre pressure setting, this works very well to alert you when a tyre is low. Obviously again uses rotations to determine tyre diameter.

[Hillbilly]

Any car speedo can legally be up to 10% <4> fast in its reading. Wifes Polo is 7k fast at 100kph.

My new Passat is 3k fast. Both are a pain in the proverbial especially the Polo

In contrast my 100 ser Landcruiser is dead on the 100k at 100kph Oh what a feeling LOL

[clip]

They cannot have any error that would allow an under read, so all manufacturers make sure they read over, just depends on how much. I know with the Tig, you could change the parameters (3 different settings from memory), but you would have to get your dealer to do this (if you haven't got the right gear).

Not sure how accurate your car GPS would be in providing a really accurate speed, the math is a little complex and depends on lots of things, least of all how good your unit actually is.