Catalytic Converter Question

Regarding a 2005 Scion XB with approximately 70600 miles on it. After a week of extremely cold weather (lows in the teens) during which the car was not driven frequently the check engine light on the car came on. Valvoline’s free diagnostic service indicated that the cause was the catalytic converter. Is it possible that the cold temperatures caused a false alarm?

No. Cold weather had nothing to do with the Check Engine coming on. But here’s the good news. If there is a problem with the catalytic converter, the vehicle manufacturer has to warranty it for 8 years/80,000 miles. So it would be replaced at no cost to you.