DTC P1153 O2 Sensor Circuit Range/Performance (High) (Bank1 Sensor1): Wiring Diagram

Fig 1: Front Oxygen Sensor Wiring Diagram - High (Bank 1 Sensor 1)

Courtesy of SUBARU OF AMERICA, INC.

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 ECM. Measure the resistance between ECM and chassis ground. Connector & terminal (B136) No. 18 - Chassis ground: (B136) No. 19 - 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 connector to ECM. Turn the ignition switch to ON. Measure the voltage between ECM and chassis ground. Connector & terminal (B136) No. 19 (+) - 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 (B136) No. 18 (+) - Chassis ground (-):	Is the voltage 4.95 V or more?	Go to step 5.	Replace the front oxygen (A/F) sensor. Refer to FRONT OXYGEN (A/F) SENSOR Front Oxygen (A/F) Sensor.
5 CHECK OUTPUT SIGNAL FOR ECM. Measure the voltage between ECM and chassis ground. Connector & terminal (B136) No. 18 (+) - Chassis ground (-): (B136) No. 19 (+) - Chassis ground (-):	Is the voltage 8 V or more?	Repair the short circuit to power in the harness between ECM and front oxygen (A/F) sensor connector. After repair, replace the ECM. Refer to ENGINE CONTROL MODULE (ECM) Engine Control Module (ECM).	Repair the poor contact of ECM connector.