I have a 2002 Denali with an ABS light that come on a few seconds after starting the engine. The code is right front speed sensor. I have replaced the sensor but still have the light. Sometimes at low speed the light will go off, and I can feel the ABS pulsing in the pedal. Given the light comes on at startup before the wheel moves, then it seems to me that something in the self test is failing, but I'm no expert. I tried to get a reading from the sensor with a multimeter, but since its AWD, I cant spin the hub even when in neutral. Any ideas?