Comment on Hotwire air speed sensor: has anyone worked with these and recognizes it?
Mpatch@lemmy.world 2 weeks ago
This is more of a personal curiosity rather than helping you.
From what I can make sense, the way this thing would work is by heating up an element. The air flow will cool the element, and the ECM measures the current needed to keep the element at a pre-set temperature.
Would that be correct?
That’s my impression, but if all you have to do is measure the current draw, then you don’t need the third wire. So I’ve built a basic ADC circuit to do that, but it’s pretty crude.
In the original monitor, it was quite precise, and so I traced the circuitry as above off that other wire. I don’t know enough about how all that works to replicate it and I can’t seem to find much about similar sensors to learn more.
If you look up dtc for mass air flow sensors you can see from their failure modes what the ecm input is supposed to be P0102 and P0103
Sorry, typically from what I remember. The third wire is typically the signal wire. You get the 12v in then ground and the 3rd wire the ecm will read the signal via voltage drop usually.
usualsuspect191@lemmy.ca 2 weeks ago
If so, I guess it would also have temperature and humidity sensors as well? Basically measuring wind chill and working backwards.