Nissan Altima L32. Manual - part 276

P0138 HO2S2

EC-225

< COMPONENT DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

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Refer to 

EC-225, "Component Inspection"

.

Is the inspection result normal?

YES

>> GO TO 15.

NO

>> GO TO 14.

14.

REPLACE HEATED OXYGEN SENSOR 2

Replace heated oxygen sensor 2.

CAUTION:

• Discard any 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 sensor, clean exhaust system threads using oxygen sensor thread cleaner

[commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant (commercial

service tool).

>> INSPECTION END

15.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-42, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection

INFOID:0000000004349271

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

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 0.68V at least once when the “FUEL INJECTION” is +25%.

“HO2S2 (B1)” should be below 0.18V 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.

PBIB3458E

EC-226

< COMPONENT DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

P0138 HO2S2

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 condition.

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 condition.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 5.

5.

CHECK HEATED OXYGEN SENSOR 2-III

Check the voltage between ECM harness connector and ground

under the following condition.

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 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.

ECM

Ground

Condition

Voltage

Connector

Terminal

F13

33

(HO2S2 

signal)

Ground

Revving up to 
4,000 rpm un-
der 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 
0.18 V at least once during this 
procedure.

JMBIA1586ZZ

ECM

Ground

Condition

Voltage

Connector

Terminal

F13

33

(HO2S2 

signal)

Ground

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 be-
low 0.18 V at least once 
during this procedure.

JMBIA1587ZZ

ECM

Ground

Condition

Voltage

Connector

Terminal

F13

33

(HO2S2 

signal)

Ground

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

The voltage should be 
above 0.68 V at least once 
during this procedure.
The voltage should be be-
low 0.18 V at least once 
during this procedure.

JMBIA1588ZZ

P0138 HO2S2

EC-227

< COMPONENT DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

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G

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EC

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• Before installing new sensor, clean exhaust system threads using oxygen sensor thread cleaner

[commercial service tool (J-43897-18 or J-43897-12)] and approved anti-seize lubricant (commercial

service tool).

>> INSPECTION END

EC-228

< COMPONENT DIAGNOSIS >

[QR25DE FOR CALIFORNIA]

P0139 HO2S2

P0139 HO2S2

Description

INFOID:0000000004349272

The heated oxygen sensor 2, after three way catalyst (manifold),

monitors the oxygen level in the exhaust gas on each bank.

Even if switching characteristics of the air fuel ratio (A/F) sensor 1

are shifted, the air-fuel ratio is controlled to stoichiometric, by the sig-

nal from the heated oxygen sensor 2.

This sensor is made of ceramic zirconia. The zirconia generates volt-

age from approximately 1V in richer conditions to 0V in leaner condi-

tions.

Under normal conditions the heated oxygen sensor 2 is not used for

engine control operation.

DTC Logic

INFOID:0000000004349273

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 oxy-

gen 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 switching response of the sen-

sor's voltage is faster than specified during the various driving condi-

tion such as fuel-cut.

DTC CONFIRMATION PROCEDURE

1.

INSPECTION START

Do you have CONSULT-III?
Do you have CONSULT-III?

YES

>> GO TO 2.

NO

>> GO TO 5.

2.

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 3.

3.

PERFORM DTC CONFIRMATION PROCEDURE

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.

SEF327R

SEF302U

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0139

Heated oxygen sensor 2 
circuit slow response

It takes more time for the sensor to respond be-
tween rich and lean than the specified time.

• Harness or connectors

(The sensor circuit is open or shorted)

• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector
• Intake air leaks