DTC P1155 O2 Sensor Circuit Range/Performance (High) (Bank 2 Sensor 1): Wiring Diagram

Fig 1: Identifying DTC P1155 O2 Sensor Circuit Range/Performance (High) (Bank 2 Sensor 1) Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE FOR SYMPTOM

Step	Check	Yes	No
1 CHECK FRONT OXYGEN (A/F) SENSOR CONNECTOR AND COUPLING CONNECTOR.	Has water entered the connector?	Completely remove any water inside.	Go to step 2.
2 CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. Turn the ignition switch to OFF. Disconnect the connectors from the ECM. Measure the resistance between ECM and chassis ground. Connector & terminal (B135) No. 11 - Chassis ground: (B135) No. 10 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 3.	Repair the ground short circuit of harness between ECM and front oxygen (A/F) sensor connector.
3 CHECK OUTPUT SIGNAL FOR ECM. Connect the ECM. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B135) No. 11 (+) - Chassis ground (-):	Is the voltage 4.5 V or more?	Go to step 5.	Go to step 4.
4 CHECK OUTPUT SIGNAL FOR ECM. Measure the voltage between ECM and chassis ground. Connector & terminal (B135) No. 10 (+) - Chassis ground (-):	Is the voltage 4.95 V or more?	Go to step 5.	Replace the front oxygen (A/F) sensor. <Ref. to FRONT OXYGEN (A/F) SENSOR .>
5 CHECK OUTPUT SIGNAL FOR ECM. Measure the voltage between ECM and chassis ground. Connector & terminal (B135) No. 11 (+) - Chassis ground (-): (B135) No. 10 (+) - Chassis ground (-):	Is the voltage 8 V or more?	Repair the short circuit to power in the harness between the ECM and front oxygen (A/F) sensor connector. After repair, replace the ECM. <Ref. to ENGINE CONTROL MODULE (ECM) .>	Repair poor contact of the ECM connector.