egt sensor The Exhaust gas temperature sensor (EGT sensor) is are installed at various points in the exhaust gas system in both diesel and petrol vehicles.And EGT sensor is responsible for reading the temperatures of the aftertreatment system components such as inlet DOC, inlet DPF, outlet DPF, inlet SCR, outlet SCR, etc., and sending this information back to the ECM to maintain proper temperatures that control the aftertreatment system to reduce the harmful emissions.