Hi, All
I was stuck in traffic one recent warm day for 45 minutes. Following that event, I had a "check engine" light. Using Torque Pro, I pulled the codes to see what happened.
I had 1 Evap failure, and 2 pending Evap failures.
I reset the codes, and have put 200 miles on it since.
What I think happened:
Our fuel injection systems are the "recirculating regulator" type. What that means is that the fuel pump, in the tank, runs wide open all the time. Any fuel that is not used by the engine is returned to the tank.
During the 45 minutes of idling, the quantity of fuel pushed into the engine compartment, warmed up, and then returned to the fuel tank generated so much vapor that it so overwhelmed the evaporative system that it threw the failure code.
Now that the code has been reset, it will probably be fine unless similar circumstances recur.
Moral of the story: Just like a loose fuel cap, a check engine light is not necessarily a hardware failure.