I am assuming this is while you are driving the vehicle? The light should come on and turn off at start up, as the ABS computer runs a self check. If the issue presents itself while driving, it is likely a wheel speed sensor that is starting to fail. If the computer looses the signal it will turn on the dash light, when it sees a signal again it will turn the light off. Could be a broken wire between the chassis and wheel speed sensor or a bad sensor. If you can, check the ABS codes, they should be stored.
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I am assuming this is while you are driving the vehicle? The light should come on and turn off at start up, as the ABS computer runs a self check. If the issue presents itself while driving, it is likely a wheel speed sensor that is starting to fail. If the computer looses the signal it will turn on the dash light, when it sees a signal again it will turn the light off. Could be a broken wire between the chassis and wheel speed sensor or a bad sensor. If you can, check the ABS codes, they should be stored.