How to check the accuracy of the speedometer

[Auristi]

If you have got navigation system on your Toyota touch with go multimedia system, you can easily check your speedometer accuracy.

1. Push and held SETUP-option on your display

2. Operate light switch five times OFF=>ON (AUTO), (SETUP-option must be held on at same time)

3. You get diagnosis Check display

4. Select NEXT PAGE

5. Next display, you can see SPEED (GPS speed)

Now you can start driving and compare your speedometer reading to SPEED reading. Usually speedometer reading is about 5 km/h too high....

To exit, push and held SETUP-option.

[FROSTYBALLS]

Within the EU, speedometers legally should never under-read and to counter this most speedometers are optimistic.

EC regulations specify that:

• The indicated speed must never be less than the actual speed, i.e. it should not be possible to inadvertently speed because of an incorrect speedometer reading.
• The indicated speed must not be more than 110 percent of the true speed plus 4 km/h at specified test speeds. For example, at 80 km/h, the indicated speed must be no more than 92 km/h.

Additionally in the UK, regulations specify that for all actual speeds between 25 mph and 70 mph (or the vehicles' maximum speed if it is lower than this), the indicated speed must not exceed 110% of the actual speed, plus 6.25 mph. For example, if the vehicle is actually travelling at 50 mph, the speedometer must not show more than 61.25 mph or less than 50 mph.

[Heidfirst]

13 hours ago, Auristi said:

Usually speedometer reading is about 5 km/h too high....

Speedo errors tend to be a % rather than a fixed amount at all speeds. 5km/h at 130km/h is not a lot whereas in a 20mph (28km/h) or 30mph (48km/h) limit it would be an offence in the UK.

In the case of my 2 Avensis it has been in the order of  ~ +6-7%.