ABS light would come on

ABS light would come on and brakes would pulse only when turning left coming to a stop. Otherwise brakes worked fine. Fluid level good. Pads were only half worn but went ahead and replaced pads on all four wheels. Calipers all looked good. No leaking or stuck calipers. After all pads replaced, brakes felt even a little better but problem still exists. Now ABS light will occasionally come on while driving but brakes work good except for initial problem of coming to a stop while turning left. If I go very slow while turning left to stop the problem does not appear. If ABS light comes on while driving, it goes off when car is turned off. When car is started again the light stays off but might come back on while driving. Any help much appreciated. Thanks