Just checked with my EF2 Ghia. It took a couple of goes but does work. I had to hold the button in for about 20 seconds, Turn Ignition on, press 3 times, and on the third time hold for about 20 seconds, then press a final time. The EF workshop manual has no information regarding this, But I know the manufacturer, VDO, has this stuff as a standard for testing there dash. I.E. My old VK Calais had the same sort of Test on it. Finally, there is a sort of bus (wire system), between the trip computer, and the dash, and the trip computer only uses fuel flow, Speed from the Sender, and Fuel Level to calculate the trip computer functions. I dont know what many of the Dash Test Values are, so I cannot compare these to the trip computer readings, but if any one has any idea of what these values are, I would greatly appreciate it if they could shed some light on the subject. (Rumour has it that the speed calculation from the sender frequency can be altered, even without the Police Dash, But I have no idea how this is done.)