MIL vs CEL lights on Cascadias

Tech explained it to me.
MIL is the computer detects something is wrong but it hasn't passed the threshold to light the CEL. Also there are MIL codes that come on that don't progress to CEL.

 

Basicially a check engine light is more serious.

I don't know about Cascadias, but my Volvo has the same thing. For example, it failed a brake test upon startup one time. That triggered the MIL. But not check engine, as it honestly had nothing to do with the engine at all. It also was able to later do the brake check and it passed, and extinguished the MIL by itself.

Another time it triggered the MIL it was indicating "excessive differential pressure across the fuel filter." What does that mean? Fuel filter is getting clogged, change it soon. It actually only came on when I was pulling hard up a hill. Which made even more sense. Swung by our shop, they changed the fuel filter and the MIL went out on its own.

Quite frankly, if a problem clears, MIL's will go out by themselves a lot of the time.

My old Cascadia threw a check engine light when it detected low coolant. Problem was, it didn't have low coolant. Try to convince the #### shop of that. They'd call me EVERY time it threw the light. And I would stop on the side of the road and check it, it's fine. I would call them back and tell them. After a half-dozen of these "call and stops" I finally told them to CHANGE THE ***KING COOLANT LEVEL SENSOR!!!! They brought me in, changed it, and lo and behold, it never came back on.

#### I hated Cascadias. And I just found out my company is getting rid of all Volvos and going to those #### crapcadias.