I have a 2005.5 tdi dsg. I was getting passed left and right so I decided to check my speedo and at 75 on the speedo I was accually going 71. I also have been keeping a log for my mpg's. The computer gives me an average of 47.5mpg but the accual is 41mpg. If any one else has this problem let vw know so we can get it fixed.
speedometer and trip comuter error
- Thread starter torqued1
- Start date
MTjake
Veteran Member
As I understand it, all VW speedometers have a built in +3 mph error intentionally. This has been my consistent experience every time I drive by one of the radar/speed displays.
I don't know why the MFA indicated MPG's can be so far off with such a precisely metered fuel system, but they're usually somewhat inaccurate in all makes and models. For instance, my friend says his Volvo XC-70 display says it gets 28 mpg. That's about a 4-5 mpg error, IIRC.
I don't know why the MFA indicated MPG's can be so far off with such a precisely metered fuel system, but they're usually somewhat inaccurate in all makes and models. For instance, my friend says his Volvo XC-70 display says it gets 28 mpg. That's about a 4-5 mpg error, IIRC.
tdisedanman
Veteran Member
I cruised from Boca Raton to Ft Myers Fl Saturday. I had a total of 4 people , used the air conditioner and was cruising about 75 -80 MPH. I got slightly over 35 MPG. I had maybe 30 local miles on the tank prior to hwy driving. However, the MAF said fuel economy was 45. something. Wow, a 10 mile per gallon difference!! This was the worst mine has been. One, and only once, I was withinn about 4 MPG but this was really off. Vw outta stop including these electronics if they are going to be so far off.
Guttboy
Veteran Member
Folks.....Report this to VWoA.....otherwise it wont get fixed.
I spoke with Uwe at Ross-Tech and it may be possible to fix this by adjusting one of the modules.
I am getting one here soon!
Regards,
Mike
I spoke with Uwe at Ross-Tech and it may be possible to fix this by adjusting one of the modules.
I am getting one here soon!
Regards,
Mike
A5JETTA
Veteran Member
Seems that if you check actual against the MAF, and it consistently gives you the same amount of error (i.e. -4 mpg)then you could just subtract "4" from your reading.
If the amount of error is consistent, I don't see anything to get all upset about; but, if the amount of inaccuracy varies--now thats a problem.
Nearly every vehicle I have owned, especially foreign vehicles, show faster speed on the speedometer than actual mph. I think this would cause everything about fuel consumption; miles to empty; etc. to be off.
Even my 1989 F150 shows more on the speedometer above 50 mph than actual speed. About 5-6 mph.
If the amount of error is consistent, I don't see anything to get all upset about; but, if the amount of inaccuracy varies--now thats a problem.
Nearly every vehicle I have owned, especially foreign vehicles, show faster speed on the speedometer than actual mph. I think this would cause everything about fuel consumption; miles to empty; etc. to be off.
Even my 1989 F150 shows more on the speedometer above 50 mph than actual speed. About 5-6 mph.
Guttboy
Veteran Member
The point is that you should not HAVE to do the math to get it right. It should work as advertised. Its like having a clock that is 13 min off....you just subtract 13 min...sorry dont like that.
In my case it is consistently 15 to 17 percent off. That is unacceptable in my book.
Speedometers can be off however, odometers should not be. My odometer is dead on whereas my speedometer is about 2.5 mph off. The two are unrelated in this case. The speedometer is I think set a tad high to avoid fines for having a speedometer that reads too low ( or so I have heard ).
In my case it is consistently 15 to 17 percent off. That is unacceptable in my book.
Speedometers can be off however, odometers should not be. My odometer is dead on whereas my speedometer is about 2.5 mph off. The two are unrelated in this case. The speedometer is I think set a tad high to avoid fines for having a speedometer that reads too low ( or so I have heard ).
jonjon
Veteran Member
Mine too Mike..
Both the MFA being 7 off, and the speedo..We discovered the error in the speedo using our portable Garmin GPS..I was a bit surprised it was off that much..And the MPG thing really sucks..The '04 Passat we had only had an error of 2mpg..I wish this was that close..Hopefully there is an adjustment..
John
Both the MFA being 7 off, and the speedo..We discovered the error in the speedo using our portable Garmin GPS..I was a bit surprised it was off that much..And the MPG thing really sucks..The '04 Passat we had only had an error of 2mpg..I wish this was that close..Hopefully there is an adjustment..
John
tdisedanman
Veteran Member
I just hope the odometer is correct else we may be getting screwed on warranty coverage.
WillR
Veteran Member
- Joined
- Mar 2, 2001
- Location
- Honey Brook, PA
on know on my 98 the ODO is dead on, but the spedo is around 3mph fast.
I will have to check the mk5 this weekend with GPS
I will have to check the mk5 this weekend with GPS
Guttboy
Veteran Member
My ODO is dead on. Verified by GPS and planning software.
tdisedanman
Veteran Member
GREAT! I am very glad to hear that. I fueled up today, and got slightly over 38 MPG but the MFA said over 44. BIG DIFFERENCE.
mullencm
New member
same here 3mph faster then my (pimp-tastic) gps says and the MPG computer show 4-6 better than at the pump.
weedeater
Top Post Dawg
IIRC, there is a method via vagcom to adjust the MFA fuel consumption figures.
Guttboy
Veteran Member
Uwe (Ross Tech owner/founder) told me on the phone 2 weekends ago that it is possible to adjust the fuel MPG computations up and down by 15% in 1% increments using the Vag Com. I have yet to attempt this as the VAG COM just arrived today. WIll keep you posted on the subject as I get time to mess with it!
Regards,
Mike
Regards,
Mike
lildevildee
Veteran Member
We just changed ours yesterday; need to fill up again and run that tank to see if I need to change the percentage again.
Guttboy
Veteran Member
Cool lemme know how it goes....going to the garage now to VAG it! Mine came in today!
lildevildee
Veteran Member
Mike, to change the % for mpg, go into instruments (below convenience group.) You should be able to find it in there; if not, I'll hook up my Vag and get the exact location for you.
torqued1, I vaguely recall seeing something for the speedo but didn't mess with it. I like having the built-in protection as I have a rather heavy right foot and enough speeding tickets to prove just how heavy my foot really is.
torqued1, I vaguely recall seeing something for the speedo but didn't mess with it. I like having the built-in protection as I have a rather heavy right foot and enough speeding tickets to prove just how heavy my foot really is.
compu_85
Gadget Guy
The EGR can't be turned down with VAG-COM on the PD engines. :S
-J
-J
lildevildee
Veteran Member
Personally, the $250 or however much it was is nothing compared to keeping my sanity intact and not having to deal with the dealership on a regular basis.
Guttboy
Veteran Member
VWoA's Official response to me is "The MFA fuel mileage calculations are not incorrect. It cannot account for wind resistance or inclination of the road."
That was that....anyone else think that this is utter and total BS????
Hell everyone of my vehicles that has a MPG calculator is within 1 or 2 mpg....not 6-7mpg off....whatever...will try to fix with the VAG COM in a couple of days.
That was that....anyone else think that this is utter and total BS????
Hell everyone of my vehicles that has a MPG calculator is within 1 or 2 mpg....not 6-7mpg off....whatever...will try to fix with the VAG COM in a couple of days.
I contacted Ross-Tech today and asked them about the ability to adjust the speedo and the mpg readings the trip computer gives. He said that he couldn't promise that the Vag-com could do these adjustments. lildevildee, help? I was going to go to VW friday and ask why, how come the Vag-com can do this an you(VW)can't? If you have the time please post as much info as you can about the abilities of the Vag-com. It would be cool if I could show the VW techs how to do it.
Thanks
Mike
Thanks
Mike
lildevildee
Veteran Member
Mike, (torqued1)
StElmo is going through now with the Vag to get the specific blocks. He'll post in a few minutes.
StElmo is going through now with the Vag to get the specific blocks. He'll post in a few minutes.
StElmo
Veteran Member
Answering for lildevildee (since I'm the one who will be looking it up anyways)
Module 17 (Instruments)
- Channel 3 allows you to adjust the consumption.
- Channel 10 allos you to adjust the average over x miles that a reading is conducted
I did not find anything for adjusting the speedo. Channel 35 allows for adjustment of the engine speed threshold. I was unable to find anything with regard to the speedo.
I do not know how the speedos we have are constructed, but if they are similiar to the ones VDO made for BMW back in the late 80's then there is a spring and a motor being controlled by electronic impulses from the speed sensor in the differential. Just my two bits from experience.
Module 17 (Instruments)
- Channel 3 allows you to adjust the consumption.
- Channel 10 allos you to adjust the average over x miles that a reading is conducted
I did not find anything for adjusting the speedo. Channel 35 allows for adjustment of the engine speed threshold. I was unable to find anything with regard to the speedo.
I do not know how the speedos we have are constructed, but if they are similiar to the ones VDO made for BMW back in the late 80's then there is a spring and a motor being controlled by electronic impulses from the speed sensor in the differential. Just my two bits from experience.
Any updateds yet? Are the changes as easy as the ross-tech website shows or do you have to use long codings? I was in the VWvortex forum,they were talking about entering long codes to get the job done. They showed the dealer and the dealer was amaized. I'm taking mine to the dealer for the mpg's being off and I want to make sure I know what I'm talking about.
lildevildee
Veteran Member
Give us 600 miles then we'll get back to you
Guttboy
Veteran Member
Hi all!
Sorry for being absent from here for a bit but was camping in the Rockies for a week.
Anyhow...VWoA called me before I left and told me that the MPG calc average has NO problem. The lady indicated that the computer cannot compensate for drag, winds, or road surface conditions.
HMMMMM....now over a 5500 mile period it is still consistently 6 mpg off. I will attempt the VAG COM adjustments this weekend.
The line from VW is BS in my opinion. Ill just compensate for the error with the VAG COM
Sorry for being absent from here for a bit but was camping in the Rockies for a week.
Anyhow...VWoA called me before I left and told me that the MPG calc average has NO problem. The lady indicated that the computer cannot compensate for drag, winds, or road surface conditions.
HMMMMM....now over a 5500 mile period it is still consistently 6 mpg off. I will attempt the VAG COM adjustments this weekend.
The line from VW is BS in my opinion. Ill just compensate for the error with the VAG COM