DTC P013A O2 Sensor Slow Response - Rich To Lean Bank 1 Sensor 2: 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 .

Fig 1: O2 Sensor Slow Response (Rich To Lean Bank 1 Sensor 2) - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from rear oxygen sensor.
   3. Disconnect the connector from ECM.
   4. Measure the resistance of harness between ECM connector and rear oxygen sensor connector.

   Connector & terminal 

   (B135) No. 57 - (E25) No. 3:

   Is the resistance less than 1 Ω?

   • Yes: Go to  2.
   • No: repair the harness and connector.
     NOTE: In this case, repair the following item:

     • Open circuit in harness between ECM connector and rear oxygen sensor connector
     • Poor contact of coupling connector
2. CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR. 

   Measure the resistance between rear oxygen sensor connector and chassis ground.

   Connector & terminal 

   (E25) No. 3 - 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 rear oxygen sensor connector.
3. CHECK REAR OXYGEN SENSOR. 

   Measure the resistance between rear oxygen sensor terminals.

   Terminals 

   No. 3 -No. 4:

   Is the resistance less than 1 Ω?

   • Yes: Replace the rear oxygen sensor. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO)>Rear Oxygen Sensor .
   • No: Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis.
     NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.