Can Speedometer be adjusted

Every Toyota I’ve owned read 2 miles high. There are several discussions on this exact Item in the forms. Personally I think it’s an appeasement to the Toyota lawyers.

 

yes, it is true. you could change tire diameters though

 

I noticed a few weeks ago that our 2008 Pontiac Vibe's speedometer shows 2mph higher than indicated by the GPS app on the phone.

 

This question about an industry standard practice is so common, we should make a Sticky thread about it.

Here is a really old article on this, from 2002:
Speedometer Scandal!

 

Make that every car made in the last 30 years or so.

The only semi-reasonable way to "fix" it is to change the size of the tires.

The real fix is: Don't worry about it.
It might keep you from getting a speeding ticket some day.

 

The usual explanation for why speedometers read high is that the manufacturers don't want owners to complain about getting speeding tickets when the speedometer said they were under the speed limit. If you look at the speed on the OBDB-2 bus, that will have the correct value, but the speedometer display is deliberately programmed to bump it up a bit.

 

i just drive 2 over

 

but does this deliberate miscalibration make you reach warranty miles sooner?

 

No. Only the speedo reads high, not the odo.

 

good news, thanks!

 

No. And there are multiple class-action lawsuits that enforced this, claiming warranty fraud. Now my new Subaru odometer reads a little bit low, the opposite behavior of its speedometer.

 

The OEM tire was a little bit smaller than what you're using now, or they calibrate it for worn tires.

 

I'd suspect with odo they do their level best to get it accurate, say consider the spec'd tire size's revs per mile half-way between brand-new and down to wear bars.

 

I was thinking they have set for worn factory tires, in order to avoid being sued,

 

I was thinking the error in mine was too large for just worn tire allowance.

 

Some cars, maybe not a Prius, one could buy aftermarket speedometer cable gears to correct a mph difference.
I would believe the dealer that this is non adjustable, especially noting laws concerning odometers.
Yes, there seems an industry variance on all speedo readings .... I recall 5% is a norm.

2 mph is very close and the fine tuning maybe chasing one's tail.
Tire diameter as the tire wears would also create a variance.

Best of luck wished.

 

Was Subaru one of those sued over warranty and odometer readings?

 

Yes. Of my household's stable, Honda was hit first, then Subaru. My current Subaru is post-settlement. No new Hondas, that was replaced by my first Prius.

That cable gear-change era ought be to nearly done now, as the cables and gears disappear, replaced by pulse counters somewhere on a drive shaft.

 

This was an important point for the regulators. In the old days, the speedometer and the odometer were mechanically linked, so tweaking one would tweak the other. Now it is all computer data, so they can program each device like they want. People who have dug into this have found that the correct speed information is on the OBD2 bus, and and can thus be recorded as needed to comply with regulations.