This Oxygen Sensor CEL-Fix is a solution for vehicles with titanium oxide sensors or "smart" Engine Control Units (ECUs) with sophisticated checks where an electronic oxygen sensor simulator cannot achieve the desired results. It is universal and applies to almost all EOBD vehicles which have two oxygen sensors (one before and one after the catalytic converter). This CEL-Fix is used to restore a normal signal for the oxygen sensor when there is an error message (CEL - Check Engine Light) in the controller. Unlike simple designs that place the sensor just a bit away from the exhaust gas stream and prevent the CEL only for short term, the CEL-Fix has an integrated mini-cat which actually improves the exhaust gas quality before it is measured by the sensor. It comes with an Oxygen Sensor Standard Thread M18x1, 5 on each side.