My Regal has times when the ABS light comes on. Seems more common with it's wet out. When the light comes on, I also get the traction light come on. Do I have a bad sensor, or perhaps a wiring issue somewhere? Where is best place to start looking? Anything common on these cars in this area? Cars got around 230,000KM.

Could be a wheel sensor, moist likely one of the front or a wiring issue to include the electrical connector for the wheel sensor at each hub. Best thing to do is get it scanned with an ABS capable scanner/scan tool to see which wheel sensor is acting up or what chassis/abs DTCs are stored.

Thanks for the info / suggestion. Is this one of those cars that you can't just replace the sensor? You actually need to change the entire bearing assembly?

Could be a wheel sensor, moist likely one of the front or a wiring issue to include the electrical connector for the wheel sensor at each hub. Best thing to do is get it scanned with an ABS capable scanner/scan tool to see which wheel sensor is acting up or what chassis/abs DTCs are stored.

That is correct. You have to replace the complete hub assembly. We have a tech procedure posted at Buick Tips & Maintenance to give you an idea of the work involved.