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

Engine Electrical System ENGINE TYPE FA (WITHOUT PUSH BUTTON START) <Ref. to 2.0L TURBO (WITHOUT PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>
Engine Electrical System ENGINE TYPE FA (WITH PUSH BUTTON START) <Ref. to 2.0L TURBO (WITH PUSH BUTTON START), WIRING DIAGRAM, Engine Electrical System.>

Fig 1: O2 Sensor Signal Biased/Stuck Rich Circuit Diagram
Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC 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 E-150 No. 15 - Chassis ground: E-150 No. 27 - Chassis ground: E-150 No. 39 - 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 HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR . Connect the connector to ECM. Disconnect the connectors from front oxygen (A/F) sensor. Turn the ignition switch to ON. Measure the voltage between ECM connector and chassis ground. Connector & terminal E-150 No. 15 (+) - Chassis ground (-): E-150 No. 27 (+) - Chassis ground (-): E-150 No. 39 (+) - 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.	Repair the poor contact of ECM connector.