Monitor Description

These DTCs are stored when there is an open or short in the air fuel ratio sensor (sensor 1) circuit, or the air fuel ratio sensor (sensor 1) output value is abnormal. The voltage of the air fuel ratio sensor (sensor 1) is monitored while the ignition switch ON, and the impedance (impedance is an electrical term that indicates the difficulty of flow of current) is checked while engine running. If the voltage of the air fuel ratio sensor (sensor 1) is outside the normal range, or the impedance is outside the normal range, the ECM illuminates the MIL and stores a DTC.