Nissan Sentra. Manual - part 382

EC-224

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

P0137 HO2S2

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 4.

4.

CHECK HEATED OXYGEN SENSOR 2-2

Check the voltage between ECM harness connector and ground as per the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 5.

5.

CHECK HEATED OXYGEN SENSOR 2-3

Check the voltage between ECM harness connector and ground as per the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Replace heated oxygen sensor 2. Refer to 

EX-5, "Exploded View"

.

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

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

The voltage should be above 
0.72 V at least once during this 
procedure.
The voltage should be below 
0.18 V at least once during this 
procedure.

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

Keeping engine speed at idle for 
10 minutes

The voltage should be above 
0.72 V at least once during this 
procedure.
The voltage should be below 
0.18 V at least once during this 
procedure.

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

Coasting from 80 km/h (50 
MPH) in D position (CVT), 5th 
position (6MT)

The voltage should be above 
0.72 V at least once during this 
procedure.
The voltage should be below 
0.18 V at least once during this 
procedure.

P0138 HO2S2

EC-225

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P0138 HO2S2

DTC Logic

INFOID:0000000009758486

DTC DETECTION LOGIC

The heated oxygen sensor 2 has a much longer switching time between rich and lean than the air fuel ratio (A/

F) sensor 1. The oxygen storage capacity of the three way catalyst (manifold) causes the longer switching

time.

MALFUNCTION A

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.

MALFUNCTION B

To judge the malfunctions of heated oxygen sensor 2, ECM monitors

whether the minimum voltage of sensor is sufficiently low during the

various driving condition such as fuel-cut.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure

before conducting the next test.

1. Turn ignition switch OFF and wait at least 10 seconds.

2. Turn ignition switch ON.

3. Turn ignition switch OFF and wait at least 10 seconds.

>> GO TO 2.

PBIB1848E

PBIB2376E

DTC No.

CONSULT screen terms

(Trouble diagnosis con-

tent)

DTC detecting condition

Possible cause

P0138

HO2S2 (B1)
(O2 sensor circuit high 
voltage bank 1 sensor 2)

A)

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

B)

The minimum voltage from the sensor is 
not reached to the specified voltage.

• Harness or connectors

(The sensor circuit is open or shorted)

• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector

EC-226

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

P0138 HO2S2

2.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A

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

>> Proceed to 

EC-227, "Diagnosis Procedure"

.

NO-1 ( With CONSULT)>>GO TO 3.
NO-2 ( Without CONSULT)>>GO TO 5.

3.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B

NOTE:

For better results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30

°C (32 to 86°F).

1. Turn ignition switch ON and select “DATA MONITOR” mode of “ENGINE” using CONSULT.

2. Start engine and warm it up to 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. Make sure that “COOLANT TEMP/S” indication is more than 70

°C (158°F).

If not, warm up engine and go to next step when “COOLANT TEMP/S” indication reaches 70

°C (158°F).

7. Open engine hood.

8. Select “HO2S2 (B1) P1146” of “HO2S2” in “DTC WORK SUPPORT” mode of “ENGINE” using CONSULT.

9. Follow the instruction of CONSULT.

NOTE:

It will take at most 10 minutes until “COMPLETED” is displayed.

10. Touch “SELF-DIAG RESULT”.
Which is displayed on CONSULT

OK

>> INSPECTION END

NG

>> Proceed to 

EC-227, "Diagnosis Procedure"

.

CAN NOT BE DIAGNOSED>>GO TO 4.

4.

PERFORM DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B AGAIN

1. Turn ignition switch OFF and leave the vehicle in a cool place (soak the vehicle).

2. Perform DTC confirmation procedure again.

>> GO TO 3.

5.

PERFORM COMPONENT FUNCTION CHECK FOR MALFUNCTION B

Perform component function check. Refer to 

EC-226, "Component Function Check"

.

NOTE:

Use component function check to check the overall function of the heated oxygen sensor 2 circuit. During this

check, a 1st trip DTC might not be confirmed.
Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Proceed to 

EC-227, "Diagnosis Procedure"

.

Component Function Check

INFOID:0000000009758487

1.

PERFORM COMPONENT FUNCTION CHECK-1

Without CONSULT

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 1 minute.

5. Check the voltage between ECM harness connector and ground as per the following condition.

P0138 HO2S2

EC-227

< DTC/CIRCUIT DIAGNOSIS >

[MRA8DE]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 2.

2.

PERFORM COMPONENT FUNCTION CHECK-2

Check the voltage between ECM harness connector and ground as per the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 3.

3.

PERFORM COMPONENT FUNCTION CHECK-3

Check the voltage between ECM harness connector and ground as per the following condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> Proceed to 

EC-227, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000009758488

1.

INSPECTION START

Confirm the detected malfunction (A or B). Refer to 

EC-225, "DTC Logic"

.

Which malfunction is detected?

A

>> GO TO 2.

B

>> GO TO 6.

2.

CHECK HO2S2 CONNECTOR FOR WATER

1. Turn ignition switch OFF.

2. Disconnect heated oxygen sensor 2 harness connector.

3. Check connectors for water.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace error-detected parts.

3.

CHECK HO2S2 GROUND CIRCUIT

1. Disconnect ECM harness connector.

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

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

The voltage should be below 0.18 V at 
least once during this procedure.

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

Keeping engine speed at idle for 10 
minutes

The voltage should be below 0.18 V at 
least once during this procedure.

ECM

Condition

Voltage

Connector

+

−

Terminal

F24

22

23

Coasting from 80 km/h (50 MPH) in D 
position (CVT), 5th gear position (6MT)

The voltage should be below 0.18 V at 
least once during this procedure.

Water should not exist.