Also had an issue with the rear center differential speed sensor which triggered my ABS light. Here's an image of the before/after:
Once cleaned and reinstalled ABS light went out, never had another issue in over 20K miles driving since.
The wiring harness connector leading into the sensor can/does become age embrittled, the locking tabs breaking away without even touching it. This could cause intermittent connection which would also trigger the ABS light.
If the sensor is replaced with new or simply removed and cleaned a dab of dielectric grease inside the terminal housing would be a good idea.
HTH