| 摘要 |
PURPOSE:To prevent the deterioration in an exhaust cleaning performance, by detecting abnormality in an electrode connection system of an oxygen pump element in accordance with a pump current flowing between electrodes of an oxygen pump element and an air/fuel ratio correction value. CONSTITUTION:A voltage VS between electrodes 17a and 17b of a battery element 19 is alternatively supplied from an A/D converter 39, a valve IP of a pump current flowing through an oxygen pump element 18, from an A/D converter 40 and the informations of throttle valve opening, absolute pressure in an intake tube, and cooling water temperature from an A/D converter 43. Upon the end of activation of an oxygen concentration sensor, a CPU 47 reads the pump current value IP to determine whether the current value IP is less than the lower limit value. When the current IP is less than the set value, a disconnection is judged as occuring in a connection line of the electrodes 17a and 17b. When a feedback correction value set according to the current IP is larger then the upper limit value, the open display of an oxygen pump element is performed. |
