The 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 PCM sets DTC P2271 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 PCM illuminates the MIL.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Electrical Monitoring | 1. Poor Connector Connection 2. Defected Downstream O2 Sensor |
Enable Conditions |
•
No fuel cut off
•
No Full load
•
No catalyst over heating protection
•
Battery voltage higher than 11V and lower than 16V | |
Threshold Value |
•
Downstream O2 Sensor Voltage less than 0.75 when lambda set point is 0.8 | |
Diagnostic Time |
•
7 sec. after lambda set point shift to corresponding side | |
MIL ON Condition |
•
2 Driving Cycle |
