I was watching one of Positive Lead Diagnostics videos the other day and while I don't remember the exact fault/diagnostics codes, etc. what stuck with me was him looking at the fault codes and saying 'OK, let's look at these PIDs'. (or something like that). That got me to wondering what built in diagnostics the ECUs now have and what 'intelligence' might be built into the high end scan tools. I know some cars have cylinder miss detection where they use sensor input to try and determine if a cylinder is misfiring. What other built in diagnostics like this are there.
I got to thinking about this as several years ago I worked on a research project where we looked at diagnosing faults with pneumatic systems using only the data already available from things like the end of stroke sensors on the air cylinders, timing out output signals sent to the solenoid coils, main air flow (and we added a pilot air flow sensor.) Using just this basic information we could determine, with good accuracy, the cause of a failure. So if a cylinder was actuating slowly we could tell if it was a solenoid issue, air leak at cylinder, etc.
Modern engines had a lot of sophisticated sensors built in and could provide more of a helping hand to the tech. As long as you know why the ECU thinks something is wrong, i.e. if it says 'IAC motor is slow' you know why it made that call and can confirm. I suspect that the high end diagnostic tools could do more of this as well, if you have code xxxx on a certain type of engine it would know that you most likely want to look at certain PIDs and would automatically set that up for you.
Perhaps some of this is done already I don't know.
