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 .

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 and 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 and 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 and 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 and 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.