| 摘要 |
PROBLEM TO BE SOLVED: To carry out malfunction diagnosis of an air-fuel ratio sensor with high accuracy for a control device of an air-fuel sensor in which the output current value varies depending on an oxygen concentration of the exhaust gas and an applied voltage. SOLUTION: When an applied voltage value corresponding to the output current value of the air-fuel ratio sensor previously stored corresponding to the operation conditions and an actual applied voltage value are compared with each other during the fuel-cut or idling operation of an engine. A judgment that voltage-current characteristics are not appropriately obtained due to the deterioration of the sensor and the like is made, and an air-fuel sensor 1 is determined to have an abnormality. COPYRIGHT: (C)2010,JPO&INPIT
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