06 Jetta speedometer problem

[JavTDi]

I'm new here at this forum. It has great info. I recently purchased a used 06 DSG Jetta tdi and noticed my speedometer is off by 5mph, ie 75 is really only 70. I used an app to track my speed and I'm consistently going 4-5mph in my Jetta. I tested this on my other vehicle and the app n speedometer were spot on.

I commute 45 highway miles one way to work and set the cruise at what I thought was 70 and the rpms were at 2300. Now I set the cruise to 70 using the app and the rpms are at 2450ish. Does this seem right or is something wrong?

 

[lilsmokey]

The Speedometer is set high from the factory. I think it is a Federal Government mandate to try to slow people people down. My car is always 3-4 high. If you are a genius with the VAG coms, I beleive there is a way that you can recalibrate it.

If you are 110% certain that your RPMS have changed the two things that come to my mind is 1) have you changed your tires or worn them down. 2) Possible Lockout problem that the transmission is not locking up in top gear and the torque converter is allowed to over-rev, where before it locked down at the lower RPM.

 

[Tim Birney]

2005.5/2006 Jetta.
75 MPH indicated is 72 MPH.
50 MPH indicated is 47 MPH.
40 MPH indicated is 37 MPH.

 

[JavTDi]

Thanks for the info. How does this affect my mpg though? My first fill up the car said 51.6 but calculated was only 45.

 

[sptsailing]

Even our cars now lie to us!

Wow. Businesses, politicians, our kids.... now even our cars are lying to us. This is disheartening....

W

Thanks for the info. How does this affect my mpg though? My first fill up the car said 51.6 but calculated was only 45.

 

[40X40]

Known issue with the 2006 Jettas. Usually the ODO is pretty close while the SPEEDO is reads quite a bit fast.

Several of us use a Scan Gauge II as a speedo.

Bill

 

[bl00tdi]

Depends on the wheel/tire package. My '06 with 235/45/17's reads about 1.5-2 MPH fast as opposed to 4-5 MPH fast with the 205/55/16's.

 

[lilsmokey]

The Multi Function display fuel economy is also a computer calculated estimate of what the car is burning. This can also be recalibrated by smart people with their vag coms. I have found that the indicated speed is off, but the odomoter actually counts pretty close. Last time I tried, between the Garmin and the car odomoter, the car was off by a half mile after 100 miles. Not to bad. Also depends on the tires and everything else. It is interesting when you can have a Michelin and Continental tire of the same sizes, though revolutions per mile are different numbers.

Everyone and everything is lying to you. My Speedo and fuel economy always counts high. I always calculate my mileage as overall between fill ups. Though some diesel pumps I have to question their accuracy. I once pumped 16.5 gallons into my Jetta and my low fuel light was not even on yet. I let the gas pump attendant have it, he said that they were just inspected last week, which is a bunch of bull. He still would not give me a discount.

 

[Joe_Meehan]

If you want to get an accurate reading, use a GPS to determine how much and in what direction the error is. The Then add to the accuracy problem is weather can also cause differences along with driving style.

 

[pnyknight]

Hmmm I thought this felt weird. I was on a test drive in a '06 TDI and speedo said 80km/h but it sure felt more closer to 60km/h. I thought the tires looked weird too but they were all 205/55/16. I had a SGII in my pocket that I only hooked up to check engine codes. If we had more time I wouldn't played around with it more.