Subaru Legacy BN/BS (2015-2019) Service Manual: Dtc p2196 a/f /o2 sensor signal biased/stuck rich bank 1 sensor 1

Subaru Legacy BN/BS (2015-2019) Service Manual / Engine (diagnostics)(h6do) / Diagnostic procedure with diagnostic trouble code (dtc) / Dtc p2196 a/f /o2 sensor signal biased/stuck rich bank 1 sensor 1

DTC DETECTING CONDITION:

Detected when two consecutive driving cycles with fault occur.

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 P2196 A/F /O2 SENSOR SIGNAL BIASED/STUCK RICH 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 connector from ECM. 3) Measure the resistance between ECM connector and chassis ground. Connector & terminal (E158) No. 46 — Chassis ground: (E158) No. 33 — Chassis ground:	Is the resistance 1 M- or more-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P2196 A/F /O2 SENSOR SIGNAL BIASED/STUCK RICH BANK 1 SENSOR 1	Repair the short circuit to ground in harness between ECM connector and front oxygen (A/F) sensor connector.
3.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 chassis ground. Connector & terminal (B136) No. 19 (+) — Chassis ground (−):	Is the voltage 4.5 V or more-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P2196 A/F /O2 SENSOR SIGNAL BIASED/STUCK RICH BANK 1 SENSOR 1	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P2196 A/F /O2 SENSOR SIGNAL BIASED/STUCK RICH BANK 1 SENSOR 1
4.CHECK OUTPUT SIGNAL FOR ECM. Measure the voltage between ECM connector and chassis ground. Connector & terminal (E158) No. 33 (+) — Chassis ground (−):	Is the voltage 4.95 V or more-	Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P2196 A/F /O2 SENSOR SIGNAL BIASED/STUCK RICH BANK 1 SENSOR 1	Replace the front oxygen (A/F) sensor. Front Oxygen (A/F) Sensor
5.CHECK OUTPUT SIGNAL FOR ECM. Measure the voltage between ECM connector and chassis ground. Connector & terminal (E158) No. 46 (+) — Chassis ground (−): (E158) No. 33 (+) — Chassis ground (−):	Is the voltage 8 V or more-	Repair the short circuit to power in the harness between ECM connector and front oxygen (A/F) sensor connector. After repair, replace the ECM. Engine Control Module (ECM)	Repair the poor contact of ECM connector.

1. OUTLINE OF DIAGNOSIS

Detect that λ value remains high.

Judge as NG if the lambda value can be determined as abnormal in accordance with driving conditions such as vehicle speed, intake air amount, and rear oxygen sensor voltage as well as front oxygen (A/F) sensor λ value.

λ value = Actual air fuel ratio/Theoretical air fuel ratio

λ > 1: Lean

λ < 1: Rich

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
Barometric pressure	≥ 75.1 kPa (563 mmHg, 22.2 inHg)
Rear oxygen sensor sub feedback	Execution
Rear oxygen sensor output voltage − Feedback target voltage	−0.2 V — 0.1 V
or rear oxygen sensor sub feedback compensation coefficient	On Min.
or rear oxygen sensor sub feedback compensation coefficient	On Max.
Intake air amount	≥ 8 g/s (0.28 oz/s)

4. GENERAL DRIVING CYCLE

Perform the diagnosis continuously after the enable conditions have been established.

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
λ value	≥ 1.15

Time Needed for Diagnosis: 10000 ms

Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.

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DTC DETECTING CONDITION:Detected when two consecutive driving cycles with fault occur.CAUTION:After servicing or replacing faulty parts, perform Clear Memory Mode Clear Memory Mode > OPERATION, and I ...

Dtc p2195 a/f /o2 sensor signal biased/stuck lean bank 1 sensor 1

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