Evaporative emission system leak detected (small leak)
The EVAP system could not hold vacuum, and the loss rate matches a small leak, roughly the size of a 0.040-inch hole. Small enough that it is very often not a failed part at all.
The EVAP monitor fails its pressure or vacuum decay test at the small-leak threshold.
Generic SAE definition. Manufacturers extend and sometimes override these, so the enhanced code on the vehicle in front of you may be narrower than what is written here.
This is the list every other P0442 page will give you. Read it, then read the part underneath it.
Every one of those 5 causes is now a decision somebody in the bay has to make, under a clock, on a car a customer wants back today.
We could mock one up. We’re not going to. A fabricated example of our own product’s output is exactly the kind of thing this page is criticizing. Verdicts appear here as the pilot produces them on real vehicles, with the evidence they actually stood on.
The pilot runs on your existing scan tool and your live repair orders. Bring us a car that's throwing this code.