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

Engine electrical system < Ref. to ENGINE ELECTRICAL SYSTEM .>

Fig 1: O2 Sensor Signal Biased/Stuck Rich - Circuit Diagram (Bank 1 Sensor 1)

G00404585

Courtesy of SUBARU OF AMERICA, INC.

DTC 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 (B136) No. 19 - Chassis ground: (B136) No. 18 - 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 (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 connector 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. < Ref. to FRONT OXYGEN (A/F) SENSOR .>
5 CHECK OUTPUT SIGNAL FOR ECM. Measure the voltage between ECM connector and chassis ground. Connector & terminal (B136) No. 19 (+) - Chassis ground (-): (B136) No. 18 (+) - 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.