Unless you plan to study automotive driveability and theory & operation of the PCM, you only need to read the codes on the odometer.
Real-time datastream results would tell you what?
I use dataloggers, scanners, occiloscopes, multimeters, .... and many years of college and continuing training classes to comprehend the datastream results.
Am I missing the point?
I mean... OK, you read a code P1450.
You look it up... P1450 = EVAP system unable to maintain required vacuum.
What do you do?
The $100 scanner gives 4 possible causes.
1 - gas cap seal
2 - EVAP pump
3- purge solenoid
4 - PCM
Do you pick the least expensive part first. Then start replacing stuff in hopes that you find the fault?
No scanner in the world (including my $2500 OTC) will tell you what's wrong. You must have the other diagnostic tools and service manuals, along with an understanding of the EVAP system.
I use this example because that's what's on my plate today. A 96 Explorer with an intermittent P1450 code.
The purge solenoid is under the battery tray and it uses a foam filter to vent tank pressure to atmosphere. My first look will be for a contaminated filter.
Any other suggestions?
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2002 Dream Cruiser #435 with: over 115hp nitrous, MX-5 "burp-free" shift mod, 2003 shifter, 2001 radio, 2001 Mopar subwoofer, MX-5 designed true cold-air intake, MX-5 designed double platinum spark plugs, shory antenna, much more....