An engine needs three things to run spark, fuel and mechanical integrity. Did the engine run well up until now? Has the van had good service history and maintenance? Was there a "Service Engine Light Soon " light on prior to the vehicle not starting? The test a garage will do will first be to look for spark at a spark plug and fuel at the fuel rail. A garage will look with a scan tool at data in the computer in your car. A computer in your car controls spark and fuel. The computer takes in inputs interprets them makes calculations and then controls the fuel injectors and when the spark arrives at the spark plugs in your engine. Crank and no start may also be related to the anti theft device in your car.