Speedometer reading way fast?

[viguanna]

I have searched and can't find anyone else talking about speedo issues so ....sorry if I am bringing this up again. I have a 2009 V6 Genesis and its by far the best car I have ever had. I thought my last fully loaded Sonota was nice but the Genesis blows it away. I have nothing negative to say except for some reason my speed is reading way fast. I took it to the local dealer, the day after I bought it and they said they reprogrammed the instrument cluster. It was about 8 MPH off, now after program its about 5 MPH off. I can understand about 2-3 mph but 5-6 seems high to me. I have double checked this with police radar as well as a separate navigation unit. Is anyone else having this issue? Yes, the faster you go the more it seems to be off. Car has factory tires and rims, 17's I think.

 

[Midnightsun]

This is by far the worst accuracy in any car I have ever owned. There was talk about this on other threads and the consensus seems to be about 2-3 mph fast at highway speeds. 5 mph is not acceptable.

 

[Hghwy52]

I also have a 2009 3.8L that reads at least 5 mph high. I think it's a problem with a lot of cars. Car makers would probably rather err on the high side since, if the speedometer read too low, the car maker could get in trouble with people speeding when the gauge said they were not. I was thinking of getting larger diameter tires when it comes time to replace the Dunlops.

 

[Midnightsun]

I also have a 2009 3.8L that reads at least 5 mph high. I think it's a problem with a lot of cars. Car makers would probably rather err on the high side since, if the speedometer read too low, the car maker could get in trouble with people speeding when the gauge said they were not. I was thinking of getting larger diameter tires when it comes time to replace the Dunlops.

OR it gets to it's out of warranty milage 10% faster than one that does read correctly.

My previous Veracruz was only about 1/2 mph fast and my Murano was actually reading 1 mph slow.

 

[STREETS]

Compared to NAVI sat speed, my speedo reads 2+ mph SLOWER which is fine by me as I tend to exaggerate the legal limit. If yours is that much over- I would go to dealer and have fix done. Especially if you are leasing- loosing miles because it thinks you are going faster/farther.

 

[Midnightsun]

Compared to NAVI sat speed, my speedo reads 2+ mph SLOWER which is fine by me as I tend to exaggerate the legal limit. If yours is that much over- I would go to dealer and have fix done. Especially if you are leasing- loosing miles because it thinks you are going faster/farther.

Hmmm, you got a special Genesis? You say yours reads slower? This means if it reads 60 you are actually going 62 according to GPS?

 

[STREETS]

My bad! Faster- stand corrected. I knew what I wanted to type- fingers did opposite! lol

 

[viguanna]

...Thank you for all the great feedback. I was thinking too about the excess mileage...running out of warranty sooner etc...I guess 5+ MPH extra over time would add to quite a bit.
I just picked up the car about 2 weeks ago. I have my own company so I am going to look back at my mileage records and see if they are more than what they used to be with my Sonota. I haven't had a chance to compare yet.
Like I said previously I had our only dealer reprogram the cluster and it helped slightly but I still think its too far off. @34 mph it reads 30 on my nav. and at 70 mph it reads 64 on my nav. , this is after the reprogram. My thought was the Genesis comes with multiple wheel sizes so the instrument cluster must be able to be programed for the size of wheel thats on the car. I used to work for volvo and BMW and we could always correct speedometer issues by telling the instrument cluster what size of rims were on the car. I thought this would be an easy fix but maybe not on our Genny's. Or ....Could it be the dealers not understanding the higher level of technology in these cars???? Hmmmmmmm, I'll keep everyone updated as I plan on going back this week to the dealer.

 

[Chopperdude]

So this may mean when I hit 140 mph on I-10 I may in fact only been doing 135 . Felt like I was only doing 80-90, no floating just smooth as silk..... still had plenty of petal I just wanted to air it out a little.

 

[Mark_888]

There have been some threads about this before, but probably not recently. My early 2009 non-Tech is about 2 faster on the odometer than actual (per my Garmin GPS). As others have said, 5 mph off is totally unacceptable.

Although the Genesis has two different wheel sizes (17 or 18 inch) the different aspect ratios of the OEM tires means that the total diameter is almost the same for both the wheel sizes. Obviously some inaccuracies in the odometer are to be expected since the total diameter changes a little bit as the tread wears.

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[Rey]

I am curious if the V-6 and V-8 speedometer electronics, calibrations, controls, etc. are identical.
I am also curious just how a dealer is able to adjust speedometer calibration? If this can be done, are there limits to the amount of adjustment the dealer can make?
These adjustments and how they are done may give some insight as to how the ECU is set up, and whether or not it can be further modified, like to remove the top speed limitation.
For the record my 4.6 is dead nuts accurate at 70 mph and stays within 1 mph much higher - all this verified by GPS.

 

[wallymn]

I spent way to much time looking into this...

The Odometer, trip computer, and NAVI all read correct speed/distance..

the speedometer is off 3 MPH at indicated 60 MPH on the v-8.. I would expect the 18 inch wheeled V6 to report the same..

to me this is BY DESIGN... if the Navi is correct, if the ODOMETER is correct, if the TRIP computer is correct (average MPH etc) the only thing left is the speedo is set to read high by design...

 

[Nabber]

Just an FYI...

A year and a half ago I posted this picture which shows my speed on three different displays; The speedo (76) the Nav unit (76) and my Radar Detector (76). A bit blurry and hard to read though.

 

[Kurt]

Have you tried borrowing someone elses portable GPS? Maybe the GPS speed is off by 5 MPH?

 

[tjc78]

Mine reads 4-5 MPH high as well (09 Non-tech). I have checked it on a TomTom GPS, an Android app on my phone, and the police radar signs.

 

[Gabe]

Mine reads 3-4mph high as well?

Verified by gps and police radar signs

What can I do about this to correct this issue?

I have a V6 premium plus/18" wheels

 

[viguanna]

Thank you for all the great feedback!!!

Kurt, I have tried this with my wifes GPS and I'm still off the same amount. I also drive by speed radars coming into the small town I live in so its a daily reminder the speedo is really off.

I am taking Genny in tomorrow to have my ....I KNOW... First scratch fixed and to have the paint coating applied, I live in SD and winters here are pretty bad with salt and chemicals etc...on the paint, I am also going to talk tech with the techs at the dealer and see if I find any information out on this "reprogram" or "speedo adjustment" they said they did. On my first trip back to the dealer after I bought Genny my salesman handled service so there is no telling what was actually done to correct the issue. I will get to the bottom of this one way or another. I have worked for Hyundai, BMW and Volvo in the past so I have a really good idea of how to handle the techs and service advisors. I'll keep posting updates as I find things out or figure them out for that matter!

Hey "chopperdude"....I had to pass 3 cars on a country highway the other day and after the third car I looked down and I was doing 120.....your right! only felt like about 80 and smooth as glass! Ok maybe it was only 115 as my speedo is off about 5mph.

 

[nb_mike]

My 2009 Genesis Sedan V6 shows 78 when my Garmin shows 75. That is pretty consistent with my car....The other thing I don't like is the car will slow or speedup by 3+ mph on hills.
But overall I love the car for ride, MPG (as much as 28+ hwy),and features.

 

[TNTitan]

I tracked mine today using GPSVP on my smartphone. 80MPH on the speedo was actually 77-78 mph ground speed. This is pretty consistent with my previous vehicles.

 

[sandy]

Every car that I've owned was like this, going a few mph slower than indicated. Same with motorcycles. Over so many cars and motorcyles over so many years, it can't be coincidence.

IMO, it must have something to do with mfg's being careful to err on the side of showing a higher speed because just imagine the liability of indicating a speed slower than the vehicle is actually going.