2003 Other Jaguar Models check engine light

i bought my jag in may of this year and every so often the check engine light will come on and with in a matter a minute the engine will over heat. we have checked the water and coolant and it has plenty. we pull off to the side of the road and let it sit for a few minutes and the tempature is back to normal, but the check engine light stays on. the light will stay on for weeks or days without it overheating. then overheat again out of the blue.