2004 Hyundai Santa Fe, check engine light just came on when turning on the heat control. What could be the causes? Heat is nice and hot, blower works great. Otherwise in excellent condition.

Hi, turning on the heater didn't cause the check engine light to come on, it just came on at the exact time. It does indicate something is going on, but if your auto is doing fine, don't panic.Usually, it indicates an emissions problem. Take you're vehicle to auto zone, and ask them if they will come out and read the code for you, they will do this for no charge, and it will tell you what the problem is. They will also give you a print out of most all the codes. I have done this several times until I bought my own obd-2 meter. After you have the code, just have them erase it with the meter to clear the check engine light. It may come back on again depending on what the problem is, but I would recommend you doing this. Cant beat it, no charge and friendly service.
Good Luck, Shastalaker7