Schley 15500. Schley 15510 and 15520. 24mm and 30mm NOX and SOOT sensors are used in Chrysler, Dodge and Jeep vehicles with 3.0L Diesel engines and other vehicles using similar sensors. The sensors are installed in the exhaust system similar O2 sensors used in gas engine vehicles and are subject to heat, rust & corrosion requiring special wrenches to remove these sensor.