My truck has the brake system warning light randomly turns on and stays on for awhile, then randomly turns off for awhile, then turns back on. When I read the obd2 code it says "ABS 01 Left Front Sensor Circuit Failure". I have tried replacing the speed sensor twice. I thought maybe it was because I had a warped rotor, but I replaced the rotor a couple weeks back. I thought it would have gone away by now. Another common cause I know of is a bad hub, but the hubs on my truck seem good. No noise, no grinding, the wheels spin smoothly, there is no vibration, there is no play in the hub, so I don't think it is the hub. I have also tested the wires that go from the sensor to the abs module, and using a multimeter for the continuity test, both wire work fine, and there is no visible damage to the wires suggesting that they are damaged and shorting out. Does anyone have any ideas as to what is causing the light? Or should I just take it to a dealership and let them deal with it?

 

The wires in there are tiny...... and can break internally. Try your continuity test again, but, while the meter is hooked up, tug/pull/twist/bend the harness over as much of it as you can reach, see if the signal drops out.

 

When I did the test the wires were bent up around the wheel well so I don't think they are broken.

 

That would explain a lot.