1995 Saab 900 se turbo won't start

car ran fine when I came home then cranks ok but won't fire. I put carb cleaner in t-body and nothing. I'm told it may be the crank sensor (where is this located and is there any pics of it) or maybe the D1 cassette? How do I find out for sure and where is the plug in for the scan tool? The car is 1995 2.0 5speed se turbo convertible with 130K miles vin #ys3df75n9s7022143