My 13 plate S went in for the clutch pedal click fix recently and I took my PID and put it into the 16 plate Greentech I was given as a courtesy car. Everything seemed to work well until I tried to use it as a Sat Nav. The voice instructions would not come through the car speakers, just from the PID itself, which made life rather difficult as, with general noise, it was virtually inaudible. Put it back in my car, everything normal. I didn't get or make any calls whilst in the Greentech so whether there would have been a problem there, I don't know.
Any ideas?