ABS Light on after brake fluid flush

I replaced my brake fluid with DOT3 fluid. Did it the same way I always do it and pumped it out using the brake pedal and cracking the bleed nipples.

After driving for a while and getting above 50ish the ABS light comes on and stays on until I shut it off, but if I shut the truck off then turn it back on it goes away, but comes back on again soon after as before.

I checked all 4 ABS sensors and none of them appear to be disconnected or have anything different about them from before. Fuse for the ABS unit is fine. The fluid is above the MIN line on the reservoir and the ABS light definitely wasn't on before I changed the fluid.

What could be causing this? Air bubble in the ABS unit? Is there a way to bleed the ABS unit or the MC on a '98? The problem seems like a direct relation to changing the fluid. I've changed brake fluid many times in the past the same way on many different vehicles and have never had any issues. What did I do wrong?

Thanks for your help!

 

Did you read the ABS code? That will tell you where to start.

 

Fill it to the max level and see if it goes away.