Nissan X-Trail 32. Manual - part 775

P0138 HO2S2

EC-229

< DTC/CIRCUIT DIAGNOSIS >

[MR20DD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

P0138 HO2S2

DTC Description

INFOID:0000000010775149

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 various driving condi-
tions such as fuel cut.

MALFUNCTION B

To judge the malfunctions of heated oxygen sensor 2, ECM monitors
whether the minimum voltage is excessively high during various driv-
ing conditions such as fuel cut.

POSSIBLE CAUSE

P0138-A

• Harness or connectors (The heated oxygen sensor 2 circuit is open or shorted.)
• Heated oxygen sensor 2

P0138-B

• Harness or connectors (The heated oxygen sensor 2 circuit is open or shorted.)
• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector

FAIL-SAFE

Not applicable

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next test.

PBIB1848E

PBIB2376E

DTC No.

CONSULT screen terms

(Trouble diagnosis content)

DTC detecting condition

P0138

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

A

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

B

The excessively high minimum voltage from the sensor is sent to ECM.

EC-230

< DTC/CIRCUIT DIAGNOSIS >

[MR20DD]

P0138 HO2S2

>> GO TO 2.

2.

DTC CONFIRMATION PROCEDURE FOR MALFUNCTION A

1.

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

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

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

4.

Check 1st trip DTC.

Is 1st trip DTC detected?

YES

>> Proceed to 

EC-231, "Diagnosis Procedure"

.

NO-1

>> With CONSULT: GO TO 3.

NO-2

>> Without CONSULT: GO TO 5.

3.

DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B-1

WITH CONSULT

Test condition : 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 with CONSULT.

2.

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

3.

Turn ignition switch OFF and wait at least 10 seconds.

4.

Restart 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.

Check that “COOLAN TEMP/S” indicates more than 70

°

C (158

°

F).

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

°

C (158

°

F).

7.

Open engine hood.

8.

Select “O2 (B1) P0138” of “HO2S2” in “DTC WORK SUPPORT” mode with CONSULT.

9.

Follow the instruction of CONSULT display.
NOTE:
It will take at most 10 minutes until “COMPLETED”is displayed.

10. Touch “SELF-DIAG RESULTS”.

Which is displayed on CONSULT screen?

OK-1

>> To check malfunction symptom before repair: Refer to 

GI-44, "Intermittent Incident"

.

OK-2

>> Confirmation after repair: INSPECTION END

NG

>> Proceed to 

EC-231, "Diagnosis Procedure"

.

CAN NOT BE DIAGNOSED>>GO TO 4.

4.

DTC CONFIRMATION PROCEDURE FOR MALFUNCTION B-2

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-1

WITHOUT CONSULT

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.
1.

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

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Restart 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 terminals under the following conditions.

P0138 HO2S2

EC-231

< DTC/CIRCUIT DIAGNOSIS >

[MR20DD]

C

D

E

F

G

H

I

J

K

L

M

A

EC

N

P

O

Is the inspection result normal?

YES-1 >> To check malfunction symptom before repair: Refer to 

GI-44, "Intermittent Incident"

.

YES-2 >> Confirmation after repair: INSPECTION END
NO

>> GO TO 6.

6.

PERFORM COMPONENT FUNCTION CHECK-2

WITHOUT CONSULT

Check the voltage between ECM harness connector terminals under the following conditions.

Is the inspection result normal?

YES-1 >> To check malfunction symptom before repair: Refer to 

GI-44, "Intermittent Incident"

.

YES-2 >> Confirmation after repair: INSPECTION END
NO

>> GO TO 7.

7.

PERFORM COMPONENT FUNCTION CHECK-3

Check the voltage between ECM harness connector terminals under the following conditions.

CAUTION:

Always drive vehicle at a safe speed.

Is the inspection result normal?

YES-1 >> To check malfunction symptom before repair: Refer to 

GI-44, "Intermittent Incident"

.

YES-2 >> Confirmation after repair: INSPECTION END
NO

>> Proceed to 

EC-225, "Diagnosis Procedure"

.

Diagnosis Procedure

INFOID:0000000010775150

1.

INSPECTION START

1.

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

EC-229, "DTC Description"

.

Which malfunction is detected?

A

>> GO TO 2.

B

>> GO TO 7.

2.

CHECK HEATED OXYGEN SENSOR 2 CONNECTOR

ECM

Condition

Voltage

Connector

+

–

Terminal

F8

57

59

Revving up to 4,000 rpm quickly under no load 
at least 10 times. (Depress and release the ac-
celerator pedal as quickly as possible.)

The voltage should be above 0.77 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

F8

57

59

Keeping engine at idle for 10 minutes.

The voltage should be above 0.77 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

F8

57

59

Coasting from 80 km/h (50 MPH) with selector 
lever in the D position.

The voltage should be above 0.77 V at 
least once during this procedure.
The voltage should be below 0.18 V at 
least once during this procedure.

EC-232

< DTC/CIRCUIT DIAGNOSIS >

[MR20DD]

P0138 HO2S2

1.

Disconnect heated oxygen sensor 2 (HO2S2) harness connector.

2.

Check that water is not inside connectors.

Is the inspection result normal?

YES

>> GO TO 3.

NO

>> Repair or replace malfunctioning part.

3.

CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT

1.

Turn ignition switch OFF.

2.

Disconnect ECM harness connector.

3.

Disconnect heated oxygen sensor 2 (HO2S2) harness connector.

4.

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

5.

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

Is the inspection result normal?

YES

>> GO TO 4.

NO

>> Repair or replace malfunctioning part.

4.

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 and ground, or ECM harness connector and
ground.

3.

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

Is the inspection result normal?

YES

>> GO TO 5.

NO

>> Repair or replace malfunctioning part.

5.

CHECK HEATED OXYGEN SENSOR 2

There is no leakage.

+

−

Continuity

HO2S2

ECM

Connector

Terminal

Connector

Terminal

CVT models

F44

1

F8

59

Existed

M/T models

F125

+

−

Continuity

HO2S2

ECM

Connector

Terminal

Connector

Terminal

CVT models

F44

2

F8

57

Existed

M/T models

F125

+

Ground

Continuity

HO2S2

Connector

Terminal

CVT models

F44

2

Ground

Not existed

M/T models

F125

+

Ground

Continuity

ECM

Connector

Terminal

F8

57

Ground

Not existed