DTC P2270: O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 2: Notes

WARNING: This page is about a different variant/trim than selected.

1. -

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM (CROSSTREK MODEL (HEV))>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO (HEV))>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO (HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Courtesy of SUBARU OF AMERICA, INC.

CHECK REAR OXYGEN SENSOR CONNECTOR .
Check the rear oxygen sensor connector.

Has water entered the connector?

Yes : Completely remove any water inside.

No : Go to 2.
CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR (OPEN) .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Disconnect the connector from the rear oxygen sensor.
4. Measure the resistance of harness between ECM connector and rear oxygen sensor connector.
  Connector & terminal
  
  (B134) No. 44 - (B19) No. 4:
  
  (B134) No. 33 - (B19) No. 3:
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 .
1. Connect the connector to ECM.
2. Turn the ignition switch to ON.
3. Measure the voltage between rear oxygen sensor connector and chassis ground.
  Connector & terminal
  
  (B19) No. 4 (+) - Chassis ground (-):
Is the voltage 1.8 V or more?

Yes : Go to 4.

No : Replace the ECM. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO (HEV))>ENGINE CONTROL MODULE (ECM) .
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) (H4DO (HEV))>REAR OXYGEN SENSOR .