ERROR DIAGNOSTIC METHOD OF UREA LEVEL SENSOR IN SELECTIVE CATALYTIC REDUCTION SYSTEM

摘要

PURPOSE: A failure diagnostic method for an element level sensor of a selective catalytic reduction system is provided to diagnose the malfunction of first to third element level sensors in order to satisfy OBD-II. CONSTITUTION: A failure diagnostic method for an element level sensor of a selective catalytic reduction system comprises following steps. Whether a first element level sensor is turned on or not is determined(S14). In case the first step is not satisfied, whether second element level sensor is turned on or not is determined(S16). In case the second step is satisfied, accumulated traveling distance is calculated from the point of time the first element level sensor is turned off(S30). Whether the accumulated traveling distance exceeds the critical traveling distance or not is determined(S32). In case the accumulated traveling distance exceeds the critical traveling distance, the malfunction of the element level sensor is determined(S34). In case the accumulated traveling distance does not exceed the critical traveling distance, the normality of the first element level sensor is determined(S36).