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

1. -

DTC detecting condition:

Detected when two consecutive driving cycles with fault occur.

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

Courtesy of SUBARU OF AMERICA, INC.

CHECK FRONT OXYGEN (A/F) SENSOR CONNECTOR AND COUPLING CONNECTOR.
1. Turn the ignition switch to OFF.
2. Check the 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 (SHORT TO GROUND).
1. Disconnect the connector from ECM.
2. Measure the resistance between the ECM connector and engine ground.
  Connector & terminal
  
  (E158) No. 3 - Engine ground:
  
  (E158) No. 4 - Engine 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 engine ground.
  Connector & terminal
  
  (E158) No. 3 (+) - Engine 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 engine ground.

Connector & terminal

(E158) No. 4 (+) - Engine 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 engine ground.

Connector & terminal

(E158) No. 3 (+) - Engine ground (-):

(E158) No. 4 (+) - Engine 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.