Hyundai Repair: Accent 98 Engine Sudden Shut Down, hiunday accent, crank sensor

Question
I have a problem with the scanner(HI Scan) it does not even recognize my Hiunday Accent 1998 when plugged and selected car and Engine.
Before using the HI SCAN my engine stopped in a sudden for several times last week and for each incident had to wait to start it again for at least 1/2 an hour.
What do you think is happening?

Answer
Will the Hi-Scan communicate when the vehicle is running?  If not, you likely have some sort of communication issue-- try selecting an Accent that's a little older or newer-- this will sometimes resolve communication issues.  If so, there's likely some sort of issue causing the ECM to shut down-- perhaps a faulty ECM relay, a problem in the ECM itself, or even an intermittent problem in the wiring.

As far as things I've seen cause this sort of issue:
-- Faulty fuel pump.  Engine performance drops off the longer the pump runs until the car just won't stay running any more.  As the car sits without running, the pump cools and will again provide enough pressure.  Tends to be worse with lower fuel levels.
-- Faulty crank sensor.  Tends to manifest itself as an abrupt engine shutoff after the engine warms up.  Often works okay after cooling.
-- Faulty alternator.  I've only ever seen this with a very good battery.  The battery drains as the car is driven because the alternator is not charging.  Because of the newness of the battery, when the car is off for a while, it is able to recover enough charge to start the engine again.