The speedometer and odometer are driven off the ABS sensor on the left front wheel and is a sine wave converted to a square wave in the ABS/ASR module. The work instructions indicate connecting and looking for a 4.0 volatge across pins 12 and 10 as the wheel spins and then using a frequency counter to check proportion to wheel speed. Also to check for voltage between pin 1 and 10 which should be battery voltage. You cant do much in the instrument panel.
I know this does not help much but gives you an idea.