so lately my CEL comes on going down a hill or going down the road but go uphill and it goes off. this makes me think there's a fluid level low. I checked all fluids and all seem fine. the rear diff has a slight leak, if that is low would it make the CEL come on? Someone mentioned some vehicles have a button to press when doing an oil change that resets the light so it knows when the oil was changed. the idea is the light comes on after 3000-5000 miles to remind you that you need a oil change. does the explorer have anything like that?