DTC P2195: A/F/O2 Sensor Signal Biased/Stuck Lean Bank 1 Sensor 1: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK FRONT OXYGEN (A/F) SENSOR CONNECTOR AND COUPLING CONNECTOR  .

   Check the following items of front oxygen (A/F) sensor.

   • Front oxygen (A/F) sensor connector
   • Coupling connector

   Has water entered the connector?

   Yes:  Completely remove any water inside.

   No:  Go to  2

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. 18 - Chassis ground:

      (B136) No. 19 - 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.

3. 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

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) (STI)>Front Oxygen (A/F) Sensor .

5. CHECK OUTPUT SIGNAL FOR ECM  .

   Measure the voltage between ECM connector and chassis ground.

   Connector & terminal 

   (B136) No. 18 (+) - Chassis ground (-):

   (B136) No. 19 (+) - 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) (STI)>Engine Control Module (ECM) .

   No:  Repair the poor contact of ECM connector.