Evaporative emission small leak code 0442...need a solution

#1
My darling 2004 LE has begun throwing code 0442 every day now for the past couple weeks and lites the mil lite aka check engine lite. It was going to the dealer for a freebie air bag ECU recall so I figured I would have them take a look see. Mileage = 145k.

They didn't find anything obvious but said they could smoke test the gas tank and fart around with it until they secured a costly repair bill. I nixed the smoke test and asked what is the most likely culprit since there is clearly a problem. They suggested a new gas cap which they installed. 12 miles later and we are back to code 0442 evap emission small leak. Has anybody been successful finding a root cause and long term solution for this little nuisance?
 
#2
I have the same problem: 2004 Corolla LE that has an engine light on since September 2016. After multiple diagnostics and repairs done, large and small, the engine light will always come back on. The code is small evaporation leak but no leaks can be found. I have replaced a gas cap twice in 90 days. As of now, the mechanics are completely clueless as to what the problem might be. Anyone has any ideas?
 
#3
Your gas cap MAY have solved your issue. There are minor and major trouble codes stored in the vehicles ECU. Evaporative emissions is a minor code. The code needs to be deleted from the ECU once the discrepancy is attended to. Remove your pos battery cable for 15 minutes then reconnect. This clears minor codes stored in the ECU and if the new cap truly fixed the issue, the CEL will stay out.
 
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