You need to run diagnostic test D07 (road speed sensor).

Enter the diagnostic mode:

Switch off Engine Run switch & switch OFF key ignition
Press both SELECT & RESET buttons and then switch ON key ignition
Keep SELECT & RESET buttons pressed for at least 8 seconds
Display then changes to "DIAG"
Release SELECT & RESET buttons
Select DIAG (not CO) by pressing again both SELECT & RESET buttons.
Select D07 by pressing SELECT (up) or RESET (down).

The D07 test display should read 000 and then as you spin the rear wheel it should count the pulses sent to the ECU and display a running total. Basically, if it counts uniformly upwards, you're good to go.

Just bear in mind, the speedo on all XTs with stock gear ratios and tyre sizes is between 8 and 10% optimistic.

BTW - The speed camera test in my first post isn't as good as the others because you'll have to wait a week to ten days for the results!

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