If you have the climate control option in your car, you can do this. When you put the car on press the Recirc button and then(keeping your finger on it)press the "up" arrow which is located three buttons above it. You will then see 1c indicated where your Temperature setting used to be. Using the other arrows to set the temperature now go to 17 then press Recirc again to see your mph, or go to 27 and press Recirc again to see your revs. To reset, press the up/down arrows for temperature change, and to adjust temperature without resetting press the Auto button then Recirc and up arrow like before to go back to either mph or Revs.
This trick is not as complicated as it seems, Try it out it s real fun!<p>T

Try it with engine running, and then engine not running with everything switched on, se what I mean, I'm gonna speak to the lads in the workshop at my dealer for more info on all 76 diagnostics.
John.