Don't know if this will work for you, but I just had the same problem on a 98 XC. My check engine light came on, My OBD reader reported the barometric sensor. I re-set the light and it came on again after a few days. At that time I removed the sensor and cleaned it, top and bottom. A large opening on the bottom and what looked to me like a very small opening on the top. Anyway, after two weeks I am still without any check engine lights. It's worth a try.