I got a weird one, my ABS works about 75% of the time, however sometimes at random the light comes on and the system turns off. I have new hubs on the front (mid grade ones, college budget) so I doubt it is that. When the light is off the system works just fine on snow and ice.

The light turns on seemingly at random. Just recently about 300 miles into a perfectly fine ride (clear roads) the light turns on. Stop to eat and the light turns off for last 350 miles with fresh snow falling. I can go weeks without seeing it come on, or days... there seems to be no obvious cause.

I live in a very cold and hilly area and would like to have the system on 100% of the time. I got 2 weeks at my parents house for break, and therefore have access to a nice warm garage. Is there an easy fix? I tried getting the code read, but whenever I do the light decides to turn off.

 

Your new hubs came also with a new ABS sensors. These sensors have several thin shims that adjust the distance of a pickup from a tooth wheel inside the hub and may require adjusting (that is by removing a shim).

 

You may have an open developing in one of your ABS wires that comes from the hub. Have you noticed if the light seems to come on after you make a turn? Start with a visual inspection of both the wires that come from each hub to where they mount on the frame. Look for chafing or any other apparent damage occuring. Turn your wheels lock to one side and inspect to see if the wire is overly taunt. For instance, turn your wheels all the way to the right, then look at the cable from where it mounts in the hub to the first clip on the upper control arm (right wheel). The cable shouldn't be tight and there should be plenty of slack. Then do the same thing for the left side.

If the visual inspection does not turn up anything, you want to check for any breaks in the wire using a good DVOM that can measure AC millivolts. Disconnect the sensor at the connector. Mine's mounted on the frame. Using T-pins back probe the connector at the wires then connect your DVOM leads to the T-pins. You want to refrain if at all possible from probing with your leads inside the connector as you could damage the connector pins. With your DVOM set on ACmv you should get a reading of 0.0mv~. Then watching the DVOM wiggle along the whole length of the cable. If you get to a spot where you get ghost voltage (reading is all over the place and won't settle) you may have found a break in the wire. You could do the same thing using your ohm scale (ohms will show "OL") if you get to an open, but the problem with that is if there is only one strand of wire, it will still show a good ohm reading (resistance for this in in the neighborhood of about 1.00 kilo ohms +/-). One strand of wire will show a good ohm reading whereas it may not be enough to carry the good AC voltage. With yours being intermittent like it is, using ACmv scale would be better.

While your on the ACmv scale steadily spin your tire with your hand and note the voltage. You should get about the same reading on both sides. The faster you spin, the higher mv. If you have a Min/Max button on your DVOM, you might want to use that as it will lock in on the highest voltage. It's kind of tough to keep a steady spin on the tire to be able to read the voltage output.

The problem may not reside with your sensors, but it is where I would start. It's simple and doesn't require you breaking out a ton of tools. Of course it's best to do this with both wheels off the ground.