Washed my engine bay out one weekend and the ses lght came on the next day. Got the codes pulled and cleared twice and ses light still comes on. I don't want to believe all four o2 sensors can go bad at once. Could it be something else causing it? I sprayed electrical corrosion blocker in the harnesses to see if it will make a difference but I havent had a chance to clear the codes again. Any other suggestions to try if that doesnt work?