'09 GT speedometer error

[Bikerscum]

Every day in my commute I pass by 3 of those road side "your speed is" things. Every time, regardless of speed, my Vibe is 4 mph high. Put in a Scangauge, & it agrees exactly with the roadside things. Anyone else have a problem? I'm thinking it's a warranty thing, I'm sure the dealer will tell me it's not. Anyone know what's involved with fixing it? Thanks

[kunkstyle]

That's a pretty common practice for all vehicles. Not just your Vibe, or even just GM. Dealer won't do anything, especially on warranty, because it's not a defect, just a built in 'factor of safety'.

[altimar]

Quote, originally posted by kunkstyle »That's a pretty common practice for all vehicles. Not just your Vibe, or even just GM. Dealer won't do anything, especially on warranty, because it's not a defect, just a built in 'factor of safety'.What he said. As they say on slashdot, 'defective by design'.

[northvibe]

Whats the % its off by? because isnt by standards/legal supoose to only be off by like 2%? or something.

[prathman]

Yes, both of our '06 Vibes have speedometers that read a little high as well. It's a common error in various makes of cars. I may get some slightly bigger diameter tires when the OEM Goodyears wear out to make the speedometer more accurate.In the US, speedometers are supposed to be within 5% by law. In Europe they can be up to 10% high but should never read lower than the actual speed.

[altimar]

Quote, originally posted by prathman »Yes, both of our '06 Vibes have speedometers that read a little high as well. It's a common error in various makes of cars. I may get some slightly bigger diameter tires when the OEM Goodyears wear out to make the speedometer more accurate.Like I said, it's intentional 'error', in that the speedometer simply shows faster than the engine computer knows it is really going. I see the same thing with my scangauge, it shows a lower speed than the speedometer. In other words, if you go with a bigger diameter tire, your odometer will be off as well as anything that the engine computer calculates using vehicle speed. Calculating your MPG will be wrong. I'm sure it's not a huge deal if you change it a few percent, but I wanted to make sure you understand what's going on.Going by the scangauge, I'd say my '07 speedo is fast by 5-7%. One of these days I intend to borrow a GPS to check/calibrate the scangauge.

[bull77]

Quote, originally posted by Bikerscum »Every day in my commute I pass by 3 of those road side "your speed is" things. Every time, regardless of speed, my Vibe is 4 mph high. what does it mean if the speed read is lower?

[prathman]

Quote, originally posted by altimar »Like I said, it's intentional 'error', in that the speedometer simply shows faster than the engine computer knows it is really going. I see the same thing with my scangauge, it shows a lower speed than the speedometer. In other words, if you go with a bigger diameter tire, your odometer will be off as well as anything that the engine computer calculates using vehicle speed. Calculating your MPG will be wrong. That's assuming that everything else is perfectly accurate to start with. My speedometer currently reads about 3% high; the odometer is closer but also slightly on the high side; and the Scangauge MPG figures were high by almost 10% before I recalibrated it.

[farles]

I tried to get an accurate reading by using the GPS on my BlackBerry as I was driving. My speedo is a little high as well, in the 2% range. This was similar on my old 2005 Vibe as well as my wife's Echo. Interesting idea...I wonder how tire wear has an impact on the speedometer reading? Must be slight, but could be measurable...

[03vibedriver]

My 09 2.4 vibe is at least 3 to 4 MPH to low on the speedometer. My ScanGauge is spot on. I am little disappointed my 03 Vibe was only 1 MPH off.

[Bikerscum]

Got a call from Pontiac yesterday, asking if there are any problems with my car. Told him about the speedo, & he said he'd pass it on to the engineers. I'm sure they'll be coming to my house soon. 4 mph to me is a bit much.... as it's across the board. Read's 29 at 25... over 14%. I'm going to take it the dealer for the first oil change & ask them to address it... let you know what happens.

[JohnC]

Quote, originally posted by Bikerscum » 4 mph to me is a bit much.... as it's across the board. Read's 29 at 25... over 8%. I'm going to take it the dealer for the first oil change & ask them to address it... let you know what happens.My 04 speedometer is correct up to 45 mph, then it starts indicating higher than actual speed. I use the scangage for speed.BTW the wifes Nissan 350Z does almost the exact thing.And don't even get me started on the temperature gage.

[Paragon]

When I first got my car I thought it felt a little slow ('09 2.4 w/ 17"). Just borrowed my friends GPS and it is showing 2 mph faster on the speedo than actual speed. Initial testing shows that it doesn't matter if you are going 25 or 65.. still 2 mph (as accurate ad I can tell with whole number output of the GPS). I knew I wasn't crackin up. My Cooper that I had was spot on with the speed check signs.. this car would give me 23 when speedo said 25.I will do some more testing throughout the week to see if it is indeed a constant difference and also to check on the odometer then I will be calling the dealer.You figure that 2 mph at 60 would result in a reading of 5000 miles instead of 4833. Do you really want your odometer off by 1667 miles when you hit 50k?It doesn't take a genius to make an accurate speed readout.

[Old Tele man]

...but, it "extends" your Warrantee MILES longer than normal!...also, those "radar" units must NOT be temperature calibrated very well (at least here in AZ), because when I go by at 55 mph in the COOL morning it displays 43 mph, but displays 56 mph when I go by in the HOT afternoon!...and I'm using cruise control at both times.

[Paragon]

From what I can tell.. as I suspected, the needle seems to be misaligned or not calibrated correctly. I think the Odometer is reading correct.