Learning the mysterious language of first gen digital cars

Just around 1995, electronics started to feature in cars. By 2000 most engines were already fully digitalized. What this means is the fuel and air mix ratio that used to be managed by a mechanical process of springs and tensioners were all done away with. Instead the entire process of internal combustion was singularly managed by an on board computer. At that period there existed two camps in the engine development unit in Toyota. The first wanted to monetize the digitalization of cars to bulk up the profits of dealerships. Since computers now featured, dealerships had to buy expensive diagnostic software and hardware to enable them to fix cars. The other school of thought in Toyota were the traditionalist who believed in the idea that since work cars such as trucks and 4X4 were used by farmers, ranchers and miners who had to operate in the field, they needed a way to diagnose problems without expensive scan tools. So these traditionalist created a rudimentary language where the cars could talk to their owners. Often these codes were primitive and confused many, but since modern cars are unsuitable for the field, only old first gen cars are really used in the field these days.