Volvo Repair: XC70 2002 starts/dies and then wont start, cam sensor, key reader

Question
I have a XC70 2002 that started and died right away and then it did not start
again, it sounds like it wants to but it will not turn over, or if it does turn over
as soon as you release the key it dies.  This happened about a month ago,
had it towed to our mechanic and it started right away for him and did not
display any codes as to what happened.  Now it is happening again.  It is
facing down hill in my driveway both times this has occurred.  I am afraid if i
have a tow truck take it in again it is going to start and make me look  crazy
again.  Last time he had it for 3 days and found nothing and could not make it
happen again.
Thank you for your thoughts.

Answer
Lisa, usually on these cars, its either an ECT sensor or a cam sensor.  It doesnt neccessarily have to show on the scanner.  It may also be the key reader.  This is a hard diagnostic issue and it has to do it for the tech so he can fix it properly.  Roger