'SpeedoHealer' is a microprocessor unit that changes the frequency of the signal from the gearbox vehicle speed sensor (VSS). Originally developed for tyre/gear changes on Bikes but very useful in cars.

http://www.bikersdiscountstore.co.uk...r-v4-pd-18.php

The MTX/IB5 gearboxes have a nylon/steel disc replacing the speedo gear on the diff. The MT285 (ST170) box was design with a VSS, so the sensor just reads the FD gear. As a result the ST170 outputs about 3.5 times more pulses per driveshaft revolution. Real pain if swapping boxes.

On the Mk1 Focus, the VSS sends its signal only to the PCM/ECU. That is then programmed to send out, according to wheel/tyre (and also the gearbox) a legacy pulse signal (for radio and cruise control) and on the digital highway. The speedo can display speed (and other measurements, on the Odometer when in diagnostic mode.

There should be detailed topics on diagnostic mode, but basiclly, hold down the odometer button whilst starting the engine. All lights come on, needles swing, then use button to scroll through various parameters.

Martin