Volkswagen Passat Forum banner

North American 2012 Passat Tdi speedometer reads 7% high

2K views 8 replies 5 participants last post by  TransWarpDrive 
#1 ·
Bought car new in March 2012. We are very happy with it, but have always wondered why we had to 'speed' to keep up with traffic. It turns out the speedo reads 7% high. Checked this with our other vehicle driving in tandem, and then with external gps which can display speed. When speedo reads 107 kph, actual speed is 100kph. I immediately thought tires are the culprit, but both sets are 94H spec tires. The service department at the dealership tells me they cannot flash the cpu to adjust the speed algorithm.

Initially it was not a big deal to me. Then I started thinking about warranty tied to kilometers on the odometer, and realized that when my odometer turns 100,000 km, the car will only have travelled 93,000 km. The extended turbo warranty is good to 193,000 km, but the car will only have travelled 179,490 km when that warranty expires. That bothers me!

The other thought I just had on this is that the fuel consumption rate is 7% higher than the advertised claims. Our car is not getting 60 mpg on the highway, but only 55.8 mpg.

Is this problem common to all North American Passats 2012 and newer? Is it only a particular year or years? Your comments will be much appreciated.
 
#2 ·
I *think* your dealership might be telling you a story, with regard to your "CPU" not being able to be re-flashed. This sounds to me like they simply do not know how to do it.

Look at it this way, the car comes from the factory with 16 and 17 and 18 inch wheels and tires, right?? That is a lot of adjust-ability right there.

And then there are the maniacs who routinely put even larger wheels on them--19s and even 20s..with no speedometer programing issues.

You need to find another service facility.

S.E.
 
#4 ·
in my 2013 i can select for different tire (or is it tyre where you are?) sizes through the mfi in the center of the dash. dont remember where that option is but i know it is there. that may not bring you back all the way to perfect but it should get a good portion of the discrepancy gone.
 
#5 ·
I can't comfirm the B7 is the same, but this has been an issue since the B5. Mine read 4-5% high, but the MPG and total mileage is accurate, it's just the speedometer that reads high. You can test this on a highway drive by comparing the odometer to the mile markers.
 
#6 ·
So here's the official VW Canada explanation (probably applies to US as well.) VW as well as other auto companies manufacturing vehicles in the U.S. have deliberately set up their vehicle speedometer displays to read high. The degree to which the speedo reads high varies by manufacturer. In the 2012 to 2014 Passat models the reading is 7.6% high. That has been changed to 4% high in the 2015 year. However, the control module for the odometer is calibrated differently and gives a very accurate reading of distance travelled. VW understood the concern about potential earlier expiration of warranty due to higher readings. This also means that mpg or liters per hundred km travelled readings are accurate. The reason for the higher speedo readings is simply to make people think they are going faster than they really are with a net effect of slower, hence safer traffic. Interesting! And NO, there is no way to adjust the speedo reading.
I can live with that. Still love the care!!
Tor
 
#9 ·
So here's the official VW Canada explanation (probably applies to US as well.) VW as well as other auto companies manufacturing vehicles in the U.S. have deliberately set up their vehicle speedometer displays to read high. The degree to which the speedo reads high varies by manufacturer. In the 2012 to 2014 Passat models the reading is 7.6% high. That has been changed to 4% high in the 2015 year. However, the control module for the odometer is calibrated differently and gives a very accurate reading of distance travelled. VW understood the concern about potential earlier expiration of warranty due to higher readings. This also means that mpg or liters per hundred km travelled readings are accurate. The reason for the higher speedo readings is simply to make people think they are going faster than they really are with a net effect of slower, hence safer traffic. Interesting! And NO, there is no way to adjust the speedo reading.
I can live with that. Still love the car!!
Tor
I heard something like that a while back. And it sounds plausible to me, given the fact that whenever I passed by one of those police radar trailers that told me my speed in flashing numbers I found I was going 2-3 MPH slower than what my speedo said it was. Hence, 25 MPH indicated was actually 22 or 23 MPH, according to the cops' radar. I noticed this phenomenon on my B5 Passat a number of times, but it really doesn't bother me all that much. No doubt I'll notice the same thing with my B7.
 
#7 ·
1998redwagon,
I actually tried that feature, but it does not address the speedo concern. It is under the winter tire option in setup. What it will do is flash a warning at you in the dash display when you exceed the speed you select in the setup to remind you that it is winter and you are going too darn fast..... Quite useful for novice drivers, and those of us not novices, but born with lead feet. Actually also quite useful for those of us who have snow and ice on roads for months each year. We do, and I think all of us know the feeling of speed creeping up on longer road trips, despite icy roads. This feature instantly alerts you when you exceed the threshold you set. Definitely a good feature.
 
#8 ·
Tor--

I have been accused of "over-thinking" things on more than one occasion

That said, I do wonder about the cruise control and its' set-point. It does seem to follow the speedometer reading, which you say is 7.6% high, by design. This is not acceptable to most folks.

If this is an example of "German Engineering" then we have discovered yet another flaw in their thinking.

No engineer, worthy of the name, would ever accept a 7.6 % read-out error.

S.E.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top