Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p0131 a/f / o2 sensor circuit low voltage bank 1 sensor 1

Subaru Legacy BN/BS (2015-2019) Service Manual / Engine (diagnostics)(h6do) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p0131 a/f / o2 sensor circuit low voltage bank 1 sensor 1

DTC DETECTING CONDITION:

Immediately at fault recognition

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and Inspection Mode Inspection Mode > PROCEDURE.

WIRING DIAGRAM:

• Engine Electrical System ENGINE TYPE EZ (WITHOUT PUSH BUTTON START) Engine Electrical System > WIRING DIAGRAM

• Engine Electrical System ENGINE TYPE EZ (WITH PUSH BUTTON START) Engine Electrical System > WIRING DIAGRAM

STEP	CHECK	YES	NO
1.CHECK FRONT OXYGEN (A/F) SENSOR CONNECTOR AND COUPLING CONNECTOR.	Has water entered the connector-	Completely remove any water inside.	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0131 A/F / O2 SENSOR CIRCUIT LOW VOLTAGE BANK 1 SENSOR 1
2.CHECK HARNESS BETWEEN ECM AND FRONT OXYGEN (A/F) SENSOR CONNECTOR. 1) Turn the ignition switch to OFF. 2) Disconnect the connectors from ECM and front oxygen (A/F) sensor. 3) Measure the resistance between ECM connector and chassis ground. Connector & terminal (E158) No. 33 — Chassis ground: (E158) No. 46 — Chassis ground:	Is the resistance 1 M- or more-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0131 A/F / O2 SENSOR CIRCUIT LOW VOLTAGE BANK 1 SENSOR 1	Repair the short circuit to ground in harness between ECM connector and front oxygen (A/F) sensor connector.
3.CHECK FOR POOR CONTACT. Check for poor contact of the front oxygen (A/F) sensor connector.	Is there poor contact of front oxygen (A/F) sensor connector-	Repair the poor contact of front oxygen (A/F) sensor connector.	Replace the front oxygen (A/F) sensor. Front Oxygen (A/F) Sensor

1. OUTLINE OF DIAGNOSIS

Detect the open or short circuit of sensor.

Judge as NG, when the element voltage is out of the specified range.

2. COMPONENT DESCRIPTION

(A)	Electromotive force	(B)	Air fuel ratio	(C)	Rich
(D)	Lean

(1)	Exhaust gas	(2)	ZrO2

3. EXECUTION CONDITION

Secondary Parameters	Execution condition
Battery voltage	≥ 10.9 V

4. GENERAL DRIVING CYCLE

Always perform the diagnosis continuously.

5. DIAGNOSTIC METHOD

If the duration of time while the following conditions are met is longer than the time indicated, judge as NG.

Judgment Value

Malfunction Criteria	Threshold Value
(1) Input voltage (+)	< 0.4 V
or
(2) Input voltage (−)	< 0.4 V
or
(3) \|Input voltage (+) − Input voltage (−)\| and 3.8 V < Input voltage (−) < 4.7 V	< 0.1 V

Time Needed for Diagnosis:

(1): 1000 ms

(2): 1000 ms

(3): 1000 ms

Malfunction Indicator Light Illumination: Illuminates as soon as a malfunction occurs.

Dtc p0132 a/f / o2 sensor circuit high voltage bank 1 sensor 1

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Other materials:

Removal
1. Disconnect the ground terminal from battery sensor. NOTE2. Release the hook, and remove the under cover assembly - passenger.3. Remove the power transistor.(1) Disconnect the connector.(2) Remove the screws and remove the power transistor. ...