I been get heavy into the scanning tools lately on my Ford van (98 e150 5.4).
Anyhow... I'm layin into it deep like all these readins of temperatures and such.
For example, I see "head cylinder temp" and it says 422 for one of 'em ... and 190 for the other one (I'm assuming there are two because there are two different readings... in farenheight I suppose)... and that gets me worried. That seems awful high.
But do I really need to worry about it? There is a check engine light after all... and it is nice and quiet.
Or let's say transmission fluid temp. It says 167. Is that too high? Do I have to look up every reading on the internet to understand it and check it every time I drive?
Half o me says hey just don't worry about all that stuff cuz it were outta the acceptable ranges the check engine light would come on for ya.
But I know for a fact the check engine light don't always come on, like lets take a simple overheat situation. Unless you got your eyes glued to the dash, the first sign o' that you gown get is pop, a hiss, and plenty o steam blindin you as you veer off the highway.
I think that's unsatisfactory. I think there outta be a coolant flow sensor (by amount per unit of time)... and I think that there outta be some kinda extreme buzzer goes off like in a airplane when it's flying to low. This is serious stuff.
So that's why I don't trust the check engine light no more.
So I guess what my specific question is, so I can avoid getting this closed again... is...
what is the specific standard on odb-ii that determines what triggers a check engine light and what don't?