The ECM 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 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 ECM illuminates the MIL.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
Signal monitoring | 1. Poor connector connection 2. Open or short to ground in circuit 3. Faulty O2 sensor 4. Faulty ECM/PCM |
Enable Condition |
•
Battery voltage is higher than 10.7V
•
Lambda value is 1.1 for 8 sec. | |
Threshold Value |
•
Downstream O2 sensor voltage is lower than 0.65V | |
Diagnostic Time |
•
10 sec. | |
MIL ON Condition |
•
2 driving cycles |
