I have a 2001 GMC Sonoma with 17,700 miles on it. I have owned it since new. While driving today in misty rain and a temp in the mid 60's my ABS warning/caution light illuminated and has remained on. I still have responsive brakes. How can I troubleshoot this system myself to determine what I need to replace? I have a decent level of understanding and experience in automotive maintenance.
It is a complex system but sometimes you can get lucky. Start by checking each of the four wheel sensors, make sure that they are connected and not damaged. Check that all fuses are good. If you have a service manual you can look up and it will give you the resistance specs for the sensor and you can measure that with an OHM meter. If not within specs replace. Also check each rotor/hub that the trigger wheel is not dirty or damaged. Check the wiring back to the control unit which is mounted under the hood unfortunattly in order to check the control unit you need specialized equipment such as a code scanner. Hope this has been helpfull. If it has please add some points to reputation for me. Thanks : D