| 摘要 |
PURPOSE:To prevent the misdiscrimination from occurring, by making a control circuit perform trouble discrimination in the said sensor on the basis of an output level of an exhaust component content sensor in case a fact that suction air temperature is one other than a high suction air temperature state of more than the specified temperature is detected. CONSTITUTION:When an engine is driven, a control circuit 20 controls a linear type solenoid valve 9 on the basis of each output of various driving state detecting devices inclusive of an oxygen content sensor 14, controlling an air-fuel ratio. In this case, at a oxygen content sensor trouble discriminating routine to be processed at the control circuit 20, first suction air temperature TA by a suction air temperature sensor 13 is compared with high suction air temperature discriminating temperature T. And, at time of TA<TA1, as well as when an engine is in a stable driving state from other engine running parameters and it is judged to be in a proper state for performing trouble discrimination of the oxygen content sensor 14, a reversal state of plus and minus signs of an air-fuel ratio compensation value is detected, and when there is no reversal of these signs within the specified time, it is judged that the oxygen content sensor 14 is out of order.
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