Hi, Ron here. - Recently my check engine light came on and at the same time the traction control lights came on and the traction control system shut down. Toyota repair shop diagnosis was front O2 sensor. Sensor was replaced w/ an OEM part. Check engine light and traction control lights went out and the traction control operates normal. Engine performance, mileage, etc., are normal. The repair shop could not explain why the failure of the O2 sensor shut down the traction control system. Anyone have an answer or idea?