Speedo out of calibration?

10264 Views 17 Replies 13 Participants Last post by TrailDust, Sep 21, 2010

ebstauffer

Discussion Starter · Apr 2, 2009

My 08 HL speedo seems to register about 2 mph faster than my actual speed. My GPS always reads 2 mph lower as did three different "You are going XX mph" speed detector. Anyone else experience this? I have the limited awd if that makes a difference.

1 - 18 of 18 Posts

TrailDust

· #2 · Apr 2, 2009 (Edited)

ebstauffer said:
My 08 HL speedo seems to register about 2 mph faster than my actual speed. My GPS always reads 2 mph lower as did three different "You are going XX mph" speed detector. Anyone else experience this? I have the limited awd if that makes a difference.

That's a known issue with most Highlander drivers I've talked to. You might like to read through this thread and also this thread that deal the speedometer error issue. Hope that helps.

Also, it depend on which wheels and tires you have mounted too. Mine is the Base trim with stock wheels and tires, and my speedometer registers 3 MPH too fast.

TrailDust

eddiefromcali

· #3 · Apr 2, 2009

My speedo reads 3mph faster than my garmin. The camry read 2mph faster as well.

deadrx7conv

· #4 · Apr 2, 2009

Automanufacturer would be liable for your speeding ticket if it read too slow.
Every vehicle I've ever driven was optimistic.

When the tires are bald, plan on moving up to a 255 tire. More choices in that size too and should 'calibrate' the speedo.

Warr1202

· #5 · Apr 2, 2009

If you figure a 2-3% error on speedometer then the odometer is probably wrong by the same amount which means you are losing approx 1500 miles off your 36k warr.

kesawi

· #6 · Apr 2, 2009

This issue has also been extensively discussed and tested on the TOCAU forum:

http://au.toyotaownersclub.com/forums/index.php?showtopic=16547

The ECU reports near the correct speed, but the speedo reads 3-4km/hr faster.

I'm not sure what the US regulations are, but Australian Design Rules stipulate the displayed speed minus true speed must be greater than or equal to 0, and less than or equal to 4km/hr plus 10% of true speed (source: http://www.trafficlaw.com.au/speedos.html). The speedo is not allowed to under-read so to ensure compliance it appears Toyota add 4km/hr on the reading to be safe.

If someone has access to the Toyota technical information, it would be nice to know if there is a procedure for removing the +4km/hr reading from the speedo. Other differences due to tyre pressure, size, tread wear, gearing, etc could then be corrected using a device such as YellR.

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yumraj

· #7 · Apr 3, 2009

this is not just a HL issue. After reading the other thread on this topic I tested my '04 Prius and in it the speedometer was showing 2 mph over the GPS.

05Moose

· #8 · Sep 3, 2010

I know it's an old thread, but I just want to say that some new people really do use the search feature.

I knew our Tacoma was off by 4 mph and could tell that our new 2010 HL was off (traffic doesn't just all drive faster just because I changed vehicles:naughty

. So good to know it's likely reading 3 mph fast. Although I'd swear from the speed of traffic that it's 4 mph off. I'll have to check it against the Tacoma since I know the exact speed on it.

So just a thanks since this is the thread I stumbled upon from my search.

TrailDust

· #9 · Sep 3, 2010

05Moose said:
I know it's an old thread, but I just want to say that some new people really do use the search feature. I knew our Tacoma was off by 4 mph and could tell that our new 2010 HL was off (traffic doesn't just all drive faster just because I changed vehicles:naughty. So good to know it's likely reading 3 mph fast. Although I'd swear from the speed of traffic that it's 4 mph off. I'll have to check it against the Tacoma since I know the exact speed on it.

So just a thanks since this is the thread I stumbled upon from my search.

If you have a handheld GPS, or can borrow one from a friend, it'll give you a speed reading withing 1/10 of a MPH to check your exact speed.

naturoses

· #10 · Sep 3, 2010

Warr1202 said:
If you figure a 2-3% error on speedometer then the odometer is probably wrong by the same amount which means you are losing approx 1500 miles off your 36k warr.

Is this normal?

Since, we lose 1500 miles out of this 36K warranty because of this inaccuracy (probably not an accident by Toyota), can we call this as a profit oriented move?

05Moose

· #11 · Sep 3, 2010

naturoses said:
Is this normal?

Since, we lose 1500 miles out of this 36K warranty because of this inaccuracy (probably not an accident by Toyota), can we call this as a profit oriented move?

No. The error isn't from the source, but rather at the speedo itself. The signal being sent is digital as is your odometer. Your speedo is analog and Toyota has an acceptible level of error in the speedo due to the conversion of the digital signal to analog. They're not cable-driven like in the past. Many others have tested the odometers and they are accurate (if not reading a little too slow which only benefits the consumer). Doing what Honda did years ago, they all know it will come back to bite them in the butt if they racked up more miles than actual on the odo.

deadrx7conv

· #12 · Sep 3, 2010

Every vehicle I've owned had an optimistic speedometer. Can you imagine the lawsuits against automakers if everyone got a speeding ticket because of a pessimistic speedometer? That is the ONLY reason that it is optimistic.

Surprisingly, the odometer for mileage seems accurate according to the mileage strips around here. No one is losing warranty mileage!

Flame Red

· #13 · Sep 3, 2010

deadrx7conv said:
When the tires are bald, plan on moving up to a 255 tire. More choices in that size too and should 'calibrate' the speedo.

Interesting idea. You are correct, a lot more choices in tires with the 255/55/19. But now the question is how much of an impact will that have on the speedometer/odometer?

This seems to be another Nanny Toyota 'feature'. I have never, ever had any car/truck speedo this far off.

Flame Red

· #14 · Sep 5, 2010 (Edited)

Found this handy dandy little tire size tool:

http://www.web-cars.com/math/tiresize.html

So going from a 245-50/19 to a 255-50/19 will result in a 2.4% reduction in speedometer. According to the calculator:

Indicated speed: 10 mph. Actual Speed: 10.1 mph.
Indicated speed: 15 mph. Actual Speed: 15.2 mph.
Indicated speed: 20 mph. Actual Speed: 20.2 mph.
Indicated speed: 25 mph. Actual Speed: 25.3 mph.
Indicated speed: 30 mph. Actual Speed: 30.4 mph.
Indicated speed: 35 mph. Actual Speed: 35.4 mph.
Indicated speed: 40 mph. Actual Speed: 40.5 mph.
Indicated speed: 45 mph. Actual Speed: 45.6 mph.
Indicated speed: 50 mph. Actual Speed: 50.6 mph.
Indicated speed: 55 mph. Actual Speed: 55.7 mph.
Indicated speed: 60 mph. Actual Speed: 60.8 mph.
Indicated speed: 65 mph. Actual Speed: 65.8 mph.
Indicated speed: 70 mph. Actual Speed: 70.9 mph.
Indicated speed: 75 mph. Actual Speed: 76.0 mph.
Indicated speed: 80 mph. Actual Speed: 81.0 mph.
Indicated speed: 85 mph. Actual Speed: 86.1 mph.
Indicated speed: 90 mph. Actual Speed: 91.2 mph.
Indicated speed: 95 mph. Actual Speed: 96.3 mph.
Indicated speed: 100 mph. Actual Speed: 101. mph.

One negative is that the "real" spare will be a different size than the tires on the car so you would only be able to use the spare temporarily at best. I never rotate the spare in anyway, so I guess that would be ok.

Given the facts that this tire change will help correct the Speedo (somewhat) and that tirerack had 13 choices for the 255 size, and 3 for the original size, going with the 255 is sounding better and better!

Any other thoughts?

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AML

· #15 · Sep 5, 2010

My Camry reads 2-3mph high as well. My Mercedes ML was dead accurate from 0 well up into the triple digits.

areamike

· #16 · Sep 9, 2010

Flame Red said:
Indicated speed: 10 mph. Actual Speed: 10.1 mph.
Indicated speed: 15 mph. Actual Speed: 15.2 mph.
Indicated speed: 20 mph. Actual Speed: 20.2 mph.
Indicated speed: 25 mph. Actual Speed: 25.3 mph.
Indicated speed: 30 mph. Actual Speed: 30.4 mph.
Indicated speed: 35 mph. Actual Speed: 35.4 mph.
Indicated speed: 40 mph. Actual Speed: 40.5 mph.
Indicated speed: 45 mph. Actual Speed: 45.6 mph.
Indicated speed: 50 mph. Actual Speed: 50.6 mph.
Indicated speed: 55 mph. Actual Speed: 55.7 mph.
Indicated speed: 60 mph. Actual Speed: 60.8 mph.
Indicated speed: 65 mph. Actual Speed: 65.8 mph.
Indicated speed: 70 mph. Actual Speed: 70.9 mph.
Indicated speed: 75 mph. Actual Speed: 76.0 mph.
Indicated speed: 80 mph. Actual Speed: 81.0 mph.
Indicated speed: 85 mph. Actual Speed: 86.1 mph.
Indicated speed: 90 mph. Actual Speed: 91.2 mph.
Indicated speed: 95 mph. Actual Speed: 96.3 mph.
Indicated speed: 100 mph. Actual Speed: 101. mph.

Interesting. My HL definitely reads 80 on the speedo when my GPS says 81. I have not tested it at other speeds though.
I have the crappy Toyo A20's on my 2010.

katekebo

· #17 · Sep 21, 2010

Car speedos are required by law to be accurate to +0/-5 mph or +0/-10% (whichever is smaller). This is to keep you on the safe side of the speed limit, especially if you decide to replace stock tires with something a little bit bigger. Motorcycle and European cars speedos tend to be more "optimistic", usually about 5 mph "on the happy side", American and Japanese cars are usually accurate to 2-3 mph at normal highway speeds. Few cars are dead on. Out of the 15 cars I have owned to date, only two were accurate to within 1 mph - a BMW series 5 and my current Toyota FJ Cruiser.

TrailDust

· #18 · Sep 21, 2010

I'm looking forward to getting new tires, and when I do I'm bumping up to 255s. I calculate that will drop my speedo error from 3 MPH too high to .5 to 1 too high.

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