ECM/PCM set P2271 code if output signal is too high at DOWN O2 sensor when AIR-FUEL ratio is under rare condition.
Item | Detecting Condition | Possible Cause |
DTC Strategy |
•
No signal activity | 1. Poor connection 2. Short to Power in signal circuit 3. HO2S(B1/S2) 4. ECM/PCM |
Enable Conditions |
•
Battery Voltage > 10.7V
•
Lambda = 0.8 for 8 sec.
•
Downstream O2S voltage > 0.65V for 95 sec.
•
Closed loop fuel control "ON"
•
3000rpm > Engine speed > 1120rpm
•
83% > Engine load > 20%
•
Air mass flow > 25kg/h
•
EGT. around downstream O2S > 700℃ or O2S heater voltage > 9.2V or Downstream O2S voltage > 0.5V
•
Readiness for operation of downstream O2S < 0.4V | |
Threshold Value |
•
Downstream O2S voltage is lower than 0.65V
•
Lambda = 1.1 for 8 sec. | |
Diagnostic Time |
•
10 sec. | |
MIL ON Condition |
•
2 Driving Cycle |
