DTC Description

The ECM/PCM tests rear O2 sensor signal level during the time the lambda target point is being shifted to lean to determine rear O2 sensor signal stuck. The ECM/PCM sets DTC P227100 if rear O2 sensor signal is above the predetermined threshold while target lambda point is being shifted to the predetermined value. If the same error code is set in the next driving cycle, the ECM/PCM illuminates the MIL.