APPARATUS AND METHOD FOR DIAGNOSING OXYGEN SENSOR OF CAR

摘要

An automotive oxygen sensor trouble diagnostic apparatus and a method thereof is provided to determine heater malfunction inside an oxygen sensor in case the inner resistance value of the oxygen sensor is over critical internal resistance value by setting up the critical internal resistance value according to the modeling value of exhaust temperature. An automotive oxygen sensor trouble diagnostic apparatus comprises: an oxygen sensor(10) sensing internal resistance value varied according to the amount of oxygen included in exhaust gas; and an engine control unit(30) receiving the internal resistance value transformed into electric signals with the oxygen sensor. The engine control unit computes modeling value of exhaust temperature. The heater error counter inside the oxygen sensor is increased in case the internal resistance value of the oxygen sensor reaches critical internal resistance value in comparison with the modeling value of the computed discharge temperature. The heater malfunction inside the oxygen sensor is determined in case the counting value of the error counter is over set value.