[lsc]

>half of the breakage in modern cars seems to require interfacing with the computer to at least clear an error flag.

Yes, you need an odbII tool. they are not expensive by the standards of decent '80s automotive tools (the cost of 'minimum viable analog tools' has dropped precipitously during my lifetime. )

The cheapest ODBII tools are bluetooth, and there is a cornucopia of apps to interface with them in the app store. You can get one that is easier to use that doesn't require a phone for $100 that will work for most problems on most cars.

(Of course, the more expensive ODBII tools are better, I'm given to understand, and allow you to do more, but you can do a lot with the cheap junk; and resetting the codes is generally the most basic functionality; unless you've got a fancy car, even the cheapest one that fits your brand should work for that. )

Having come of age at a time when I was driving and repairing (older) carberuated vehicles, I personally think that fixing a carb is like a thousand times harder than interfacing with the ODB system. Modern injection systems just solve so many problems without trying.

My experience of the modern diagnostic systems is that it's actually way easier. The scan tool saves you so much time and effort vs. the old manuals "go to page 5 if it doesn't X, 32 if it does" A lot of the time, the cheap scan tool gives you a code and description; you punch that into a search engine and you get a goddamn video of someone doing the repair. It's amazing compared to screwing around with an exploded parts diagram. (I mean, from the perspective of someone who isn't really a car guy) - I mean, there's always problems the scantool doesn't catch, but... I mean, I'm talking about all this from a shadetree perspective, there have always been a lot of automotive problems I couldn't fix, just 'cause I'm not an automotive specialist.

[nradov]

An ODBII is helpful for basic stuff but it doesn't get you very far with modern cars. Most manufacturers now have specialized proprietary scanners which are needed for any complex repairs, especially for anything electronic. Those scanners are extremely expensive and sometimes only sold to authorized service centers.

[fragmede]

Are these manufacturers called BMW, by any chance? They sell this authorized "computer module" replacement part for $400. But if you take it apart, there's a 50 cent fuse inside that was blown. Replacing the fuse does no good without access to the proprietor BMW software, because the module will refuse to work after the fuse is replaced until it is reset using their software. Which means you have to pay for a whole new module. However not all manufacturers are like that. After I change the oil on my Honda, there's a silly little dance to reset the oil life indicator, but nothing too crazy. The Toyota Corolla is a favorite for self-driving car enthusiasts due to the hackability of its lane-guidance system into something fuller. I'm also disappointed in some of the directions the future has taken us (it's frustrating to me how hard it is the replace user-servicable parts inside a lot of laptops, eg Apple), but not all manufacturers are the same and talking about the situation as if they are is too abstract to be useful, say, when looking for your next car.