I have a 2004 Hyundai Santa Fe with a 3.5L engine, AWD (4WD), with front and back ABS disk brakes, and 93,800 miles. (This is the same vehicle that I had to oil pressure light and oil sludge issues with a few weeks ago. The problem started after all of that was resolved, but I doubt that the two things are related).
The ABS light has recently started coming on, but only in certain circumstances. The ABS light only comes on after I have been driving for a while (maybe 30+ minutes or so) on an Interstate highway or other high speed road. Usually, once it comes on, it stays on until I reach my destination. Then after I turn off the car and wait a while, the ABS light does not come back on when I restart the car. It never comes on when doing local lower speed driving, even if I am driving locally for 30, 40, 50 minutes or more.
I had a flat tire fixed and tires rotated about 6 weeks ago and they mentioned then that the back brakes are getting worn and need new disks and rotors. About a week ago, I had the brakes checked all around, and they said the front brakes are fine but the back brakes did need new disks and rotors, so I had that done. The ABS light problem happened before getting the brakes repaired, and it continues to happen after the brake repairs were done.
My hearing isn't the best, but people riding in my car say they can hear a slight possible wheel bearing and/or clicking sound coming from the right rear wheel area while riding. I don't hear it, but they say the sound does not seem to increase or decrease with changes in the speed of the car. I mentioned noise issue when I had the brakes checked and the rear brakes repaired. They checked the wheel bearings and couldn't find anything wrong with them and no play in the wheels etc.
Here's my question: How would a dealership or auto repair place go about trying to find out what is causing the ABS light to come on? I am guessing that they can hook the car up to a computer and look for the error code, but wouldn't that only work if and when they can get the ABS light to come on?