On a T595 with a Sagem MC2000 ECU -- none of the diagnostics or tests work on TuneECU 18.104.22.168. The Map Edit function works fine, allowing tune to be read from ECU and altered. Haven't tried writing one back though.
Using TuneECU Lite 1.2 all the diagnostics work but its a bit hit or miss whether clicking on the tick boxes works or not, sometimes you have to quit and start again.
On the Dealertool all the diagnostics work and are done immediately as soon as you press the button.
So a bit of fine tuning still to be done by Alain but for a ten quid outlay
A lot of diagnostic function like fan and rev-counter test don't seem supported. Still an exceptional piece of free software though