Nissan March K13. Manual - part 239

P0138 HO2S2

EC-417

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 2)]

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P0138 HO2S2

DTC Logic

INFOID:0000000006046437

DTC DETECTION LOGIC

The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen sensor 1. The oxygen
storage capacity of the three way catalyst (manifold) causes the
longer switching time.
To judge the malfunctions of heated oxygen sensor 2, ECM monitors
whether the voltage is unusually high during the various driving con-
dition such as fuel cut.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.

>> GO TO 2.

2.

PERFORM DTC CONFIRMATION PROCEDURE

1.

Start engine and warm it up to normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

4.

Let engine idle for 2 minutes.

5.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Go to 

EC-417, "Diagnosis Procedure"

.

NO

>> INSPECTION END

Diagnosis Procedure

INFOID:0000000006046438

1.

CHECK GROUND CONNECTION

1.

Turn ignition switch OFF.

2.

Check ground connection E38. Refer to Ground Inspection in 

XX-XX, "*****"

.

Is the inspection result normal?

YES

>> GO TO 2.

NO

>> Repair or replace ground connection.

2.

CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1.

Disconnect heated oxygen sensor 2 (HO2S2) harness connector.

2.

Disconnect ECM harness connector.

3.

Check the continuity between HO2S2 harness connector and ECM harness connector.

PBIB1848E

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0138

Heated oxygen sensor 2 
circuit high voltage

An excessively high voltage from the sensor 
is sent to ECM.

• Harness or connectors

(The sensor circuit is open or shorted)

• Heated oxygen sensor 2

EC-418

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 2)]

P0138 HO2S2

4.

Also check harness for short to ground and short to power.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair open circuit or short to ground or short to power in harness or connectors.

3.

CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT

1.

Check the continuity between HO2S2 harness connector and ECM harness connector.

2.

Check the continuity between HO2S2 harness connector or ECM harness connector and ground.

3.

Also check harness for short to power.

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair open circuit or short to ground or short to power in harness or connectors.

4.

CHECK HO2S2 CONNECTOR FOR WATER

Check connectors for water.

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace harness or connectors.

5.

CHECK HEATED OXYGEN SENSOR 2

Refer to 

EC-418, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 6.

NO

>> Replace heated oxygen sensor 2.

6.

CHECK INTERMITTENT INCIDENT

Refer to 

XX-XX, "*****"

.

>> INSPECTION END

Component Inspection

INFOID:0000000006046439

1.

INSPECTION START

Do you have CONSULT-III?

Do you have CONSULT-III?

YES

>> GO TO 2.

NO

>> GO TO 3.

2.

CHECK HEATED OXYGEN SENSOR 2

HO2S2

ECM

Continuity

Connector

Terminal

Connector

Terminal

F45

1

F8

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Existed

HO2S2

ECM

Continuity

Connector

Terminal

Connector

Terminal

F45

4

F8

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Existed

HO2S2

ECM

Ground

Continuity

Connector

Terminal

Connector

Terminal

F45

4

F8

50

Ground

Not existed

Water should not exist.

P0138 HO2S2

EC-419

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 2)]

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With CONSULT-III

1.

Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.

2.

Start engine and warm it up to the normal operating temperature.

3.

Turn ignition switch OFF and wait at least 10 seconds.

4.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

5.

Let engine idle for 1 minute.

6.

Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select “HO2S2 (B1)” as the monitor item with
CONSULT-III.

7.

Check “HO2S2 (B1)” at idle speed when adjusting “FUEL INJECTION” to 

±

 25%.

“HO2S2 (B1)” should be above 0.68 V at least once when the “FUEL INJECTION” is + 25%.
“HO2S2 (B1)” should be below 0.36 V at least once when the “FUEL INJECTION” is 

−

 25%.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 6.

3.

CHECK HEATED OXYGEN SENSOR 2-I

Without CONSULT-III

1.

Start engine and warm it up to the normal operating temperature.

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Start engine and keep the engine speed between 3,500 and 4,000 rpm for at least 1 minute under no load.

4.

Let engine idle for 1 minute.

5.

Check the voltage between ECM harness connector and ground under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 4.

4.

CHECK HEATED OXYGEN SENSOR 2-II

Check the voltage between ECM harness connector and ground under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

JSBIA0082GB

ECM

Condition

Voltage

Connector

Terminal

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−

F8

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(HO2S2 signal)

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Revving up to 4,000 rpm under no load at least 
10 times

The voltage should be above 0.68 V at 
least once during this procedure.
The voltage should be below 0.36 V at 
least once during this procedure.

ECM

Condition

Voltage

Connector

Terminal

+

−

F8

50

(HO2S2 signal)

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Keeping engine speed at idle for 10 minutes

The voltage should be above 0.68 V at 
least once during this procedure.
The voltage should be below 0.36 V at 
least once during this procedure.

EC-420

< DTC/CIRCUIT DIAGNOSIS >

[HR12DE (TYPE 2)]

P0138 HO2S2

NO

>> GO TO 5.

5.

CHECK HEATED OXYGEN SENSOR 2-III

Check the voltage between ECM harness connector and ground under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 6.

6.

REPLACE HEATED OXYGEN SENSOR 2

Replace heated oxygen sensor 2.

CAUTION:

• Discard any heated oxygen sensor which has been dropped from a height of more than 0.5 m (19.7

in) onto a hard surface such as a concrete floor; use a new one.

• Before installing new heated oxygen sensor, clean exhaust system threads using Oxygen Sensor

Thread Cleaner (commercial service tool) and approved Anti-seize lubricant (commercial service
tool).

>> INSPECTION END

ECM

Condition

Voltage

Connector

Terminal

+

−

F8

50

(HO2S2 signal)

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Coasting from 80 km/h (50 MPH) in D position 
(A/T), 4th gear position 

The voltage should be above 0.68 V at 
least once during this procedure.
The voltage should be below 0.36 V at 
least once during this procedure.