DTC P0159 O2 Sensor Circuit Slow Response (Bank 2 Sensor 2)

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.
GENERAL DESCRIPTION < Refer to DTC P0159 O2 SENSOR CIRCUIT SLOW RESPONSE (BANK 2 SENSOR 2) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

CAUTION: After repair or replacement of faulty parts, perform Clear Memory Mode < Refer to OPERATION , CLEAR MEMORY MODE > and Inspection Mode < Refer to PROCEDURE , INSPECTION MODE >.

WIRING DIAGRAM:

Fig 1: Heated Rear Oxygen Sensor - Wiring Diagram

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC CHART

Step	Check	Yes	No
1 CHECK ANY OTHER DTC ON DISPLAY.	Is any other DTC displayed?	Check DTC using "List of Diagnostic Trouble Code (DTC)". < Refer to LIST OF DIAGNOSTIC TROUBLE CODE (DTC) . > NOTE: In this case, it is not necessary to inspect DTC P0159.	Go to step 2.
2 CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR. Turn the ignition switch to OFF. Disconnect the connector from ECM and rear oxygen sensor. Measure the resistance of harness between ECM and rear oxygen sensor connector. Connector & terminal (B135) No. 15 - (E25) No. 3:	is the resistance less than 1 Ω?	Go to step 3.	Repair the open circuit of harness between ECM and rear oxygen sensor connector.
3 CHECK HARNESS BETWEEN ECM AND REAR OXYGEN SENSOR CONNECTOR. Measure the resistance between rear oxygen sensor harness connector and chassis ground. Connector & terminal (B25) No. 3 - Chassis ground:	Is the resistance more than 1 MΩ?	Go to step 4.	Repair the chassis short circuit of harness.
4 CHECK REAR OXYGEN SENSOR. Measure the resistance between connector terminals of rear oxygen sensor. Terminals No. 3 - No. 4	Is the resistance less than 1 Ω?	Replace the rear oxygen sensor. < Refer to REAR OXYGEN SENSOR . >	Temporary poor contact occurs. Check poor contact of connector.