exhuast warning?

On my 2000 1200 limited editon the exhuarst warning light comes on. What can sause this probelm? I measured the resistance on the two temp sensors, one is 2 ohms and the other 7 ohms, I dont know what they should read. I also just did a complete rebuild. In turn I premixed the gas ans also used the oiler to make sure the engine would have a good break in period. Im not sure if to much oil would cause the problem. I have almost ran all the oil out and the warning still occurs. Please help.