DTC P2271: O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 2: Notes
DTC detecting condition:
Detected when two consecutive driving cycles with fault occur.
- After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>CLEAR MEMORY MODE . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>INSPECTION MODE ..
- Use the check board when measuring the ECM terminal voltage and resistance.
Wiring diagram:
Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .
- CHECK REAR OXYGEN SENSOR CONNECTOR AND COUPLING CONNECTOR
.
Check the rear oxygen sensor connector and coupling connector.
Yes: Completely remove any water inside.
No: Go to 2
- CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR
.
- Turn the ignition switch to OFF.
- Disconnect the connector from the rear oxygen sensor connector.
- Disconnect the connector from ECM.
- Measure the resistance of harness between ECM connector and rear oxygen sensor connector.
Connector & terminal
(E158) No. 42 - (E25) No. 3:
(E158) No. 16 - (E25) No. 4:
Is the resistance less than 1 Ω?
Yes: Go to 3
No: Repair the open circuit of harness between ECM connector and rear oxygen sensor connector.
- CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR
.
Measure the resistance between the ECM connector and engine ground.
Connector & terminal
(E158) No. 16 - Engine ground:
Is the resistance 1 MΩ or more?
Yes: Go to 4
No: Repair the short circuit to ground in harness between ECM connector and rear oxygen sensor connector.
- CHECK EXHAUST SYSTEM
.
Check exhaust system parts.
NOTE: Check the following items.- Looseness and improper fitting of exhaust system parts
- Damage (crack, hole etc.) of parts
- Damage (crack, hole etc.) between front oxygen (A/F) sensor and rear oxygen sensor
Is there any fault in exhaust system?
Yes: Repair or replace faulty parts.
No: Replace the rear oxygen sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>REAR OXYGEN SENSOR .