DTC P2196 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 Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO) > Clear Memory Mode > OPERATION , and Inspection Mode Ref. to ENGINE (DIAGNOSTICS) (H4DO) > Inspection Mode > PROCEDURE .

WIRING DIAGRAM:

Engine Electrical System NON-TURBO MODEL (WITHOUT PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System > NON-TURBO MODEL (WITHOUT PUSH BUTTON START) .
Engine Electrical System NON-TURBO MODEL (WITH PUSH BUTTON START) Ref. to WIRING SYSTEM > Engine Electrical System > NON-TURBO MODEL (WITH PUSH BUTTON START) .

Fig 1: Engine Electrical System Non-Turbo Model 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 connector and chassis ground.
  Connector & terminal
  
  (B136) No. 19 - Chassis ground:
  
  (B136) No. 18 - Chassis ground:
Is the resistance 1 MΩ or more?

Yes: Go to 3 .

No: Repair the short circuit to ground in harness between ECM connector and front oxygen (A/F) sensor connector.
CHECK OUTPUT SIGNAL FOR ECM .
1. Connect the connector to ECM.
2. Turn the ignition switch to ON.
3. Measure the voltage between ECM connector and chassis ground.
  Connector & terminal
  
  (B136) No. 19 (+) - Chassis ground (-):
Is the voltage 4.5 V or more?

Yes: Go to 5 .

No: Go to 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?

Yes: Go to 5 .

No: Replace the front oxygen (A/F) sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO) > FRONT OXYGEN (A/F) SENSOR .
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?

Yes: 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 FUEL INJECTION (FUEL SYSTEMS) (H4DO) > ENGINE CONTROL MODULE (ECM) .

No: Repair the poor contact of ECM connector.