Infiniti QX56 (Z62). Manual - part 569

EC-254

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0138, P0158 HO2S2

11.

CHECK HEATED OXYGEN SENSOR 2

Refer to 

EC-254, "Component Inspection (HO2 sensor 2)"

.

Is the inspection result normal?

YES

>> GO TO 13.

NO

>> GO TO 12.

12.

REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning heated oxygen sensor 2. Refer to 

EM-40, "Exploded View"

.

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 oxygen 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

13.

CHECK INTERMITTENT INCIDENT

Refer to 

GI-40, "Intermittent Incident"

.

>> INSPECTION END

Component Inspection (HO2 sensor 2)

INFOID:0000000006217820

1.

INSPECTION START

Will CONSULT-III be used?

Will CONSULT-III be used?

YES

>> GO TO 2.

NO

>> GO TO 3.

2.

CHECK HEATED OXYGEN SENSOR 2

 WITH CONSULT-III

1.

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

2.

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

3.

Let engine idle for 1 minute.

4.

Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select “HO2S2 (B1)/(B2)” as the monitor item
with CONSULT-III.

5.

Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to 

±

25%.

“HO2S2 (B1)/(B2)” should be above 0.74 V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)/(B2)” should be below 0.18 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.

JMBIA1573GB

P0138, P0158 HO2S2

EC-255

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

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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 terminals 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 terminals under the following conditions.

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 terminals under the following conditions.

Is the inspection result normal?

YES

>> INSPECTION END

NO

>> GO TO 6.

6.

REPLACE HEATED OXYGEN SENSOR 2

Replace malfunctioning heated oxygen sensor 2. Refer to 

EM-40, "Exploded View"

.

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.

ECM

Condition

Voltage

Connector

+

–

Terminal

Terminal

F110

96

[HO2S2 

(bank 1)]

100

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

The voltage should be above 0.74 V at 
least once during this procedure.
The voltage should be below 0.18 V at 
least once during this procedure.

87

[HO2S2 

(bank 2)]

ECM

Condition

Voltage

Connector

+

–

Terminal

Terminal

F110

96

[HO2S2 

(bank 1)]

100

Keeping engine at idle for 10 minutes

The voltage should be above 0.74 V at 
least once during this procedure.
The voltage should be below 0.18 V at 
least once during this procedure.

87

[HO2S2 

(bank 2)]

ECM

Condition

Voltage

Connector

+

–

Terminal

Terminal

F110

96

[HO2S2 

(bank 1)]

100

Coasting from 80 km/h (50 MPH) with se-
lector lever in the D position

The voltage should be above 0.74 V at 
least once during this procedure.
The voltage should be below 0.18 V at 
least once during this procedure.

87

[HO2S2 

(bank 2)]

EC-256

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

P0138, P0158 HO2S2

• Before installing new oxygen 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

P0139, P0159 HO2S2

EC-257

< DTC/CIRCUIT DIAGNOSIS >

[VK56VD]

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P0139, P0159 HO2S2

DTC Logic

INFOID:0000000006217821

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 various driving conditions
such as fuel cut.

DTC CONFIRMATION PROCEDURE

1.

PRECONDITIONING

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.

Will CONSULT-III be used?

YES

>> GO TO 2.

NO

>> GO TO 4.

2.

PERFORM DTC CONFIRMATION PROCEDURE

 WITH CONSULT-III

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

°

C (32 to 86

°

F).

1.

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

2.

Turn ignition switch OFF and wait at least 10 seconds.

3.

Turn ignition switch ON.

4.

Turn ignition switch OFF and wait at least 10 seconds.

5.

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

6.

Let engine idle for 1 minute.

7.

Select “DATA MONITOR” mode with CONSULT-III.

8.

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 to 70

°

C (158

°

F).

9.

Open engine hood.

10. Select “HO2S2 (B1) P0139” or “HO2S2 (B2) P0159” of “HO2S2” in “DTC WORK SUPPORT” mode with

CONSULT-III.

11. Start engine and follow the instruction of CONSULT-III display.

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

12. Touch “SELF-DIAG RESULTS”.

SEF302U

DTC No.

Trouble diagnosis name

(Trouble diagnosis content)

DTC detecting condition

Possible cause

P0139

HO2S2 (B1)
[Heated oxygen sensor 2 
(bank 1) circuit slow response]

It takes more time for the sensor to respond 
between rich and lean than the specified 
time.

• Harness or connectors

(The heated oxygen sensor 2 circuit is 
open or shorted)

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

P0159

HO2S2 (B2)
[Heated oxygen sensor 2 
(bank 2) circuit slow response]