If only that were true. The only codes that are "industry standard" are the ones defined by OBDII and they are ECM/emissions centric. They are dwarfed by the number of OEM specific codes assigned not just to ECM functions but to all of the other controllers on the vehicle - body controller, transmission controller, stability control system, entertainment controller,, yadda yadda yadda. A generic scan tool can't even see them because they are stored in the vehicle specific controller memory. I have a BMW specific scan tool app that runs on my phone and the last time I scanned my 2007 BMW 3 series it logged 30+ DTC's of which only one - a BMW specific code, was the one causing the MIL to illuminate. Something arcane about an intermittent slow response from the electronic thermostat. I cleared it and the MIL went out but the other codes were still present. Of them the only one of interest was a failure of the right front ride height sensor. Until I ran the scan I had no idea it was not functioning.At least on our cars and truck, it throws a standard code that is industry wide standard, and there is plenty of information on the webs to self diagnose and repair it.
Just changing a battery in a modern car can be an exercise in frustration. The intelligent charging system on the BMW has to be programmed when a new battery is installed - they call it "battery registration". You have to enter battery type (AGM/FLA) and AH capacity. That resets the controller's charging profile which changes as the battery ages. If you don't "register" your new battery you run he risk of improper charging and the dreaded "walk home". That's just one of many services that can't be performed without a vehicle specific scan tool and the data for your make and model year. Fortunately BMW has made all of that free to the public but putting together a dealer service center level dedicated PC to running all that the free code will still cost you better part of grand just for the computer and cabling. My little $150 phone app can handle simple tasks like battery registration or a brake fluid purge but it is far from comprehensive.