Suddenly had an F40 on the Electric Kenmore Oasis Dryer ( circa 2008). I recalled this happened on days when the outdoor temps hit high 80's with high humidity. My vent is close to the ground and there was a pile of mulch directly under it. So I scooped it out around the vent......then unplugged the 220 plug. Let it sit ( I didn't turn off the circuit breaker) for around 4 minutes....... plugged it back in then restarted the load. I selected NORMAL LOAD AND NORMAL DRYNESS LEVEL and IT Worked like a charm. No more F40 code. Now If I could get my Oasis to quit the F1 codes at the start of the washing ( When you see F1, press off, start....off, start,......off, start ( 3 times in a row ) and the washer will run. Now I'm getting F1 at the end of the Wash cycle on some settings. Press off and start once or twice and it goes into the rinse cycle. Sometimes F1 will appear in the Rinse cycle......again press F1 once or twice or 3 times and it will finish. TIME TO SHOP FOR A NEW pair, but as long as it's working...