DTC P2196 A/F/O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1: Notes

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Clear Memory Mode . and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DOTC)>Inspection Mode .
Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram:

Fig 1: A/F/O2 Sensor Signal Biased/Stuck Rich Bank 1 Sensor 1 - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

CHECK FRONT OXYGEN (A/F) SENSOR CONNECTOR AND COUPLING CONNECTOR.
Has water entered the connector?
- Yes : Completely remove any water inside.
- No : Go to 2.
CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR.
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Measure the resistance between ECM and chassis ground.
  Connector & terminal
  
  (E158) No. 15 - Chassis ground:
  
  (E158) No. 27 - Chassis ground:
  
  (E158) No. 39 - Chassis ground:
  
  Is the resistance 1 MΩ or more?
- Yes : Go to 3.
- No : Repair the ground short circuit of harness between ECM and front oxygen (A/F) sensor connector.
CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR.
1. Connect the connector to ECM.
2. Disconnect the connectors from front oxygen (A/F) sensor.
3. Turn the ignition switch to ON.
4. Measure the voltage between ECM and chassis ground.
  Connector & terminal
  
  (E158) No. 15 (+) - Chassis ground (-):
  
  (E158) No. 27 (+) - Chassis ground (-):
  
  (E158) No. 39 (+) - Chassis ground (-):
  
  Is the voltage 8 V or more?
- Yes : Repair the short circuit to power in the harness between ECM and front oxygen (A/F) sensor connector.
- No : Repair the poor contact of ECM connector.