DTC P2196 O2 Sensor Signal Biased/Stuck Rich (Bank 1 Sensor 1): Wiring Diagram

Engine Electrical System ENGINE TYPE FB (WITHOUT PUSH BUTTON START) <Ref. to ENGINE PERFORMANCE (Legacy), ENGINE PERFORMANCE (Outback), Engine Electrical System.>
Engine Electrical System ENGINE TYPE FB (WITH PUSH BUTTON START) <Ref. to ENGINE PERFORMANCE (Legacy), ENGINE PERFORMANCE (Outback), Engine Electrical System.>

Fig 1: O2 Sensor Signal Biased/Stuck Rich (Bank 1 Sensor 1) - Wiring Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTICS PROCEDURE

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 connector from ECM. Measure the resistance between ECM connector and chassis ground. Connector & terminal (E158) No. 46 - Chassis ground: (E158) No. 33 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 3 .	Repair the short circuit to ground in harness between ECM connector 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 connector and chassis ground. Connector & terminal (E158) No. 46 (+) - 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 connector and chassis ground. Connector & terminal (E158) No. 33 (+) - 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 connector and chassis ground. Connector & terminal (E158) No. 46 (+) - Chassis ground (-): (E158) No. 33 (+) - Chassis ground (-):	Is the voltage 8 V or more?	Repair the short circuit to power in the harness between ECM connector and front oxygen (A/F) sensor connector. After repair, replace the ECM. <Ref. to ENGINE CONTROL MODULE (ECM) .>	Repair the poor contact of ECM connector.