So my check engine light came on about 5 minutes after driving away from the shop that replaced a faulty heater core today. I'm planning to give the shop a call tomorrow to see if they can check it out quickly, but any ideas on what might be the cause? I've put about 2,000 miles on it since the last oil change and about 1,000 miles since the last tune-up. Both of the those jobs were done at Toyota dealer shops, but the heater core job wasn't. What are the chances something got disturbed during the heater core installation? Or is it possible I just need to do a reset? For this model, does turning the car on and off three times in quick succession reset the light?