DIY Speedo Calibration

[Lightflyer1]

60 it is for me too. I will try and do this at our GTG in Seguin this weekend.

 

[Jettageek1962]

Take some pictures

Lightflyer1, If you are able to do this during your GTG this weekend, please take some additional pictures to post to this. Thanks

 

[Lightflyer1]

Like what exactly did you have in mind? Seems pretty staight forward from what I read and saw. Just let me know what you want pictures of and I will try.

 

[buckeye96]

I did a quick check on my speedo going to work this morning. I have not done the mod yet but probably will. It has to be a vag.com thing, cause my difference between the 2 is not consistent.

Speedo Real Difference
10 8 2
20 18 2
30 27 3
40 36 4
50 45 5
60 55 5
70 64 6
80 73 7

Cmon VW. ***

 

[mheat]

... I have a scan-guage II, so I know
my speed any time I want.

Bill

I just checked my scan-gauge with the GPS, and the scan gauge out of the box was reading between 3% and 4% slow (this is adjustable on the scan-gauge in 1% increments).

 

[CADtechTDi]

Here's my Speedo vs. GPS comparison readings in MPH, before modifying anything. Note: I locked on using cruise control; but interestingly, could not get the needle to stay EXACTLY on top of each number - so I set cruise to nearest position just below each Speedo setting...

Speedo GPS Diff.
30-ish 28-ish 2-ish (didn't use cruise)
40 37.4 2.6
50 47.6 2.4
60 56.5 3.5
70 66.4 3.6
80 76.5 3.5
85 80.8 4.2
90 85.3 4.7

Of course, 80, 85 and 90 were purely hypothetical, right? Since I would never knowingly break any speed limits on purpose.

Now, still not sure if I want to try twisting on that needle...

 

[40X40]

I just checked my scan-gauge with the GPS, and the scan gauge out of the box was reading between 3% and 4% slow (this is adjustable on the scan-gauge in 1% increments).

Thanks for the reminder!! My gps is via laptop and requires a
passenger for safe operation(also to take notes!!).

Bill

 

[Letemfly]

Couple things to think about.
Your GPS May assume you are traveling in a straight line at a constant altitude. It can see hills and will indicate curves but how accurate is it on a hill or curve for actual MPH across the highway? Those both would give you a lower MPH than you actually were traveling right?
As far as the VAG-COM is it only reading the RPM and GEAR? Do you tell it what size your tires are to get the MPH or is it assuming you have average tires. So how accurate is it really? If you have bigger tires than "average" you are going to be going faster than the VAG-COM thinks unless you can, and have told it the actual diameter of your tires.
Are you controlling all the variables when you determine how much your VW speedo is in error?

 

[Lightflyer1]

I am going to base my "adjustment" on the climatronic display at 60 mph. I will check it against my gps as well. The climatronic seems to agree with the stationary radar gun that is around the road construction near my house. It is one of those that have a billboard to remind you how fast you are going in the construction zone.

 

[y2khardtop]

Letemfly, you must live in the mountains. Can't speak for the VAG-COM, but my GPS data was done on flat ground.

The only "variable" I can't account for is VW's total lack of quality control in this regard (love the car otherwise)

 

[dschein]

Has anyone read VW Technical Bulletin 2012684?

It describes a condition where the "Speedometer Indicated Speed is Greater than Actual Vehicle Speed". Sounds like my car. It appears this could be caused by a setting in the "Instrument Cluster Code".

My car will be hooked up to a Vag-Com on Tuesday and this is one of the things I plan to check.

 

[dschein]

Today MPGeez! made the "VW Technical Bulletin 2012684" mod to my car. We did a brief test drive and it appears to be fixed. When I make the 60 mile drive home from work tonight I'll verify that and post my results.

 

[Lightflyer1]

Check your odometer as well. If this is the same TSB it will fix the speedo but throw the odo off.

 

[RickD]

So far,I'm satisfied with the "needle adjustment",I may try the same fix on our RABBIT soon,gotta make sure the better half is not around,she'd get nervous if she saw her brand new speedo on the kitchen table !!

 

[dschein]

My earlier positive report was based on a drive around the block but not at highway speeds. Tonight after getting up to speed, the GPS read 70 MPH and the spedo was (still) at 72 . So the change we made today did not affect the spedo. I'll have to clock the odometer tomorrow on a multi mile run and see how far its off and if it matches the spedo.

 

[jvc]

Why not just stop by your local VW dealer and have the tire ratio programming changed on the VAG, i.e. change last digit from the european tire ratio of 3 to a 7 TSB #900601 October 20 2006
John

 

[dschein]

My earlier positive report was based on a drive around the block but not at highway speeds. Tonight after getting up to speed, the GPS read 70 MPH and the spedo was (still) at 72 . So the change we made today did not affect the spedo. I'll have to clock the odometer tomorrow on a multi mile run and see how far its off and if it matches the spedo.

Tonight I did a test of the spedo and odometer - keep in mind this is -after- doing the tire ratio change as defined in the TSB (change 3 to 7). The spedo is off by ~ 2.8%, it displays faster than the actual speed. The odometer is off by ~ 1.7%, it displays less miles than actually traveled. Where to go next? Who knows . . . . I don't

 

[40X40]

Tonight I did a test of the spedo and odometer - keep in mind this is -after- doing the tire ratio change as defined in the TSB (change 3 to 7). The spedo is off by ~ 2.8%, it displays faster than the actual speed. The odometer is off by ~ 1.7%, it displays less miles than actually traveled. Where to go next? Who knows . . . . I don't

Please tell us your methodology.....err, How did you run the test???

Bill

 

[jackbombay]

Tonight I did a test of the spedo and odometer - keep in mind this is -after- doing the tire ratio change as defined in the TSB (change 3 to 7). The spedo is off by ~ 2.8%, it displays faster than the actual speed. The odometer is off by ~ 1.7%, it displays less miles than actually traveled. Where to go next? Who knows . . . . I don't

If you want both right you have to undo the tire ratio change and move the needle as depicted in the first post of this thread, there is no other way to do it.

 

[dschein]

Please tell us your methodology.....err, How did you run the test???

Bill

I used a GPS for MPH and mile markers for the trip meter / odometer test.

This was done on a 35 / 36 mile segment of the PA Turnpike at a constant speed of 70 MPH.

 

[dschein]

If you want both right you have to undo the tire ratio change and move the needle as depicted in the first post of this thread, there is no other way to do it.

It's ovious the tire ratio fix didn't change the spedo. So are you saying that the tire ratio fix only affected the odometer?

 

[jackbombay]

From all I've read there seems to be a set discrepency between the odo and speedo, any software changes will maintain that discrepency.

 

[dschein]

UPDATE: I changed Address 17 to "0023201" from "0023203" today.

The GOOD news is that the speed shown in Vag-Com now matches my GPS and it appears that the odometer (trip meter) is also correct .

The BAD news is that the speedometer is farter off than before. It reads 74 MPH when the GPS reads 70 .

 

[DieselDavid]

The BAD news is that the speedometer is farter off than before.

That is probably why the speedometer on the instrument cluster is behind a clear plastic cover!

 

[dschein]

Confirmed on a 90+ mile drive this morning that using the setting #1 (full list below) my trip meter and vag-com speed (km/h) are spot on with the GPS.

For now I'll live with a correct odometer and a speedometer that reads fast.

4 - 21848
3 - 21960
2 - 22076
1 - 22188
5 - 22304
6 - 22420
7 - 22532

 

[spraycast]

Would you provide me a link or tell me where to find VW Technical Bulletin 2012684?

Thank you.

 

[Lightflyer1]

It is in the Bentley manual. I don't know if it is okay or possible to copy it here though.

 

[bondtimbond]

The photos don't appear to be showing anylonger in the original post on teh DIY fix. Anyone know what happened to them? Can someone repost the original with the photos? Thanks.

 

[y2khardtop]

guys, sorry my photos have vanished. I will try and track them down, or take my wife's car apart again.

VW is not my primary car, so I forgot about this thread. Will try and repost them.

 

[bondtimbond]

WHere are the photos????