Quote Originally Posted by Rumcajs View Post
I'd like to know how it works because a diode is "electrical one way valve" and not a resistor. So my understanding is that at best it blocks the voltage/current one way and let it flow other. So what is changing?
Do you have a means of reading MAF signal? If you do, how is the diode affecting the value?

Cheers
A characteristic of a diode is it will also have a voltage drop of 0.5 to 0.6 across it.

So in theory you should also see this voltage difference at the ECU.