The PCM/ECM tests rear HO2S signal level during the time the lambda target point is being shifted to rich to determine rear HO2S signal stuck. The PCM/ECM sets DTC P2270 if rear HO2S signal is below 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 PCM/ECM illuminates the MIL.
Item | Detecting Condition | Possible cause |
DTC Strategy |
•
Plausability check during shift of lambda setpoint to rich or lean ( after P2096 / P2097 detection) | 1. Poor connection or damaged harness 2. Rear HO2S |
Enable Conditions |
•
No fuel cut-off
•
No full load phase
•
No catalyst overheating protection
•
11V < Battery voltage < 16V | |
Threshold value |
•
Rear HO2S signal < 0.75V when lambda set point = 0.80
•
Downstrem O2 sensor signal too low | |
Diagnosis Time |
•
7 sec after lambda set point shift to corresponding side | |
MIL On Condition |
•
2 Driving Cycles |
