well iim going to scan it tomorrow but heres what happened. when i cranked the engine today at work to leave i noticed a roaring sound that ive never noticed before when letting it warm up. so after i drove off the battery light came on about a minute later. it stayed on until i got home which was about 4 miles. the temp stayed the same so im pretty sure the noise wasnt the water pump bearings, but i did smell burning rubber. i have 130k on it. would the belt and tension pully cause this to happen? it is in need of replacement just going off mileage alone. lights seemed to work to as did the ac. so im thinking either belt/pully or altenator. but whats causing the roaring noise and smell? could the ac compressor be going out?