> “The alternator is supposed to output a steady nominal 12V”
I know that but it is stepped down for electronics to 5V. When I wrote that the 5V comes from the alternator, I didn’t write it was stepped down from 12V because I wanted to be short and didn’t think it was necessary to insert detail.
Electrical and Electronics are separated by scale. Of course, car electrical components operate at 12V and electronics have had a 5V supply for impedance matching. Impedance matching is the reason why there’s a lower voltage norm.
Electronics can be fried easily if voltage swings. I know the onboard computer control modules have voltage regulators built into their input or on the circuit card. They will never rely on a higher voltage alternator which can degrade with time.
But you miss the bigger point as you think you’re somehow so knowledgeable about the minutiae.
Do you know what the bigger point is?
No, I don’t think so, You’re too hung up with drawing attention to yourself lecturing on distractive details.
No. I simply chose a single point that you were wrong on out of *many* as a single example because I’d be throwing a wall of text up if I were to explain every point you were wrong on and why in depth. A lot of the electronic, not the electrics, on a modern car actually does operate on that nominal 12V and does not rely on the PCM/ECU for voltage regulation.
To choose another single point of the many, Limp Home mode is actually not for ‘security’ but for safety reasons.
I build EFI/engine management systems for fun, profit and racing.