I was an ASE mechanic and I didn't know how to work a carburetor or timing light at the time. ASE test dosen't really cover the older stuff anymore. Its more modern and up to date with the technology being used in today's cars and trucks.
If all it took was to plug in a computer and fix it I would have never left the field. Its not that straight forward. Yes the scantool does give you trouble codes and those give you an idea on where to start looking. And yes you plug in the codes to the computer and it gives you a trouble tree but unless your up to date with training, good luck. New technology is always emerging, try interpreting a schematic for these newer cars.
Before I left the chevy house I found out that the fuel pumps have their own computer outside the tank thats separate from all the rest.
