Also - and this may more directly answer your question - OBDII codes are designed and mandated by the government. Each manufacturer is required to include a very specific set of emissions related codes, whether they directly apply to that vehicle or not.
I'm waiving a big disclaimer flag here, because I am not a mechanic and because I am going to use a bit of speculation on the exact example you've listed -
When a fault is generated in your BMW, it is the factory diagnostic system doing the warning. The 'closest' OBDII code is also generated per government mandate. So, your car may throw a 'code 77' (which is not the actual digits displayed by the Peake tool, as clarification), which may mean different things in different BMWs. Perhaps in an M3, you'd see the appropriate OBDII code for the temperature (as a hypothetical).