| 摘要 |
A method for judging break-down of a rear oxygen sensor is provided to decide the malfunction of the functional unit of the rear oxygen sensor by comparing the deterioration-to-driving distance degrees of two front oxygen sensors. A method for judging break-down of a rear oxygen sensor comprises the steps of: determining the deterioration of the rear oxygen sensor(S30); driving the vehicle under stable driving condition in which it is determined that the rear oxygen sensor is not deteriorated(S40); determining whether a front oxygen sensor makes output more than a% under the stable driving condition(S50); comparing the deterioration-to-driving distance degree of a normal front oxygen sensor with that of the current front oxygen sensor(S60); determining whether the error rate of the deterioration-to-driving distance degree of the front oxygen sensor to the deterioration-to-driving distance degree of the normal front oxygen sensor is within b%(S70); and determining malfunction of the rear oxygen sensor by using CTS(Cold Trip Sum), WTS(Wet Trip Sum), MTS(Medium Trip Sum), HTS(Hot Trip Sum) and TTS (Total Trip Sum)(S80).
|
