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Are you sure it actually says "service engine soon" and not something else? When this light comes on it shoudl store a P code.
If you reset the codes does the light come on right away?
Here is a link that explaiins how to check/reset codes.....So reset codes then start vehicle and write down the codes that come back right away......Then drive vehicle until check engine light comes on, check codes again and let me know what they are. Thanks.
If vehicle runs good then its likely something minor but I cant say what until I know the code. You can have the code checked and reset for free at your local parts store. Your vehicle you might not be able to check codes on dash......If you could take a picture of your dash/heat assembly I could help. There are two different ways for this vehicle if you look in that article. Let me know if you have questions, thanks.
With this vehicle you should be able to check codes by press/holding off and warmer or off and passenger side warmer. Then press high/low to toggle through options. Let me know if you get the code. Thanks.