Car in shop during -50 weather

On the weekend my engine light on my car came on. The car seemed to be working fine so this might just be an indicator malfunctioning from the cold, or it could be something serious. Refrained from driving yesterday. This morning it was around -50 with the windchill again (-35 without) so the car didn't want to start. Eventually the plug in warmed it up enough that I got it to the garage but they'll not have time for it until tomorrow. Spent most of my day preparing for class but the more I work, the less ready I feel.