Infiniti FX35 / FX45. Manual - part 376

 

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Infiniti FX35 / FX45. Manual - part 376

 

 

DTC P0139, P0159 HO2S2

EC-265

< SERVICE INFORMATION >

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DTC P0139, P0159 HO2S2

Component Description

INFOID:0000000001326092

The heated oxygen sensor 2 (HO2S2), after three way catalyst 1,
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.

CONSULT-III Reference Value in Data Monitor Mode

INFOID:0000000001326093

Specification data are reference values.

On Board Diagnosis Logic

INFOID:0000000001326094

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 before the three way catalyst 1 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

INFOID:0000000001326095

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

 WITH CONSULT-III

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

°

C (32 to 86 

°

F).

SEF327R

MONITOR ITEM

CONDITION

SPECIFICATION

HO2S2 (B1)
HO2S2 (B2)

• Revving engine from idle to 3,000 rpm quickly after the following conditions 

are met

- Engine: After warming up
- Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and 

at idle for 1 minute under no load

0 - 0.3V 

←→

 Approx. 0.6 - 1.0V

HO2S2 MNTR(B1)
HO2S2 MNTR(B2)

LEAN 

←→

 RICH

SEF302U

DTC No.

Trouble diagnosis name

DTC detecting condition

Possible cause

P0139
0139
(Bank 1)

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

(Heated oxygen sensor 2 circuit is open 
or shorted)

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

P0159
0159
(Bank 2)

EC-266

< SERVICE INFORMATION >

[VQ35DE]

DTC P0139, P0159 HO2S2

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.

Make sure 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).

7.

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

8.

Start engine and following the instruction of CONSULT-III.
NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.

9.

Make sure that “OK” is displayed after touching “SELF-DIAG RESULTS”.
If “NG” is displayed, refer to 

EC-270, "Diagnosis Procedure"

.

If “CAN NOT BE DIAGNOSED” is displayed, perform the following.

a.

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

b.

Return to step 1.

Overall Function Check

INFOID:0000000001326096

Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a 1st
trip DTC might not be confirmed.

 WITH GST

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.

Set voltmeter probes between ECM terminal 74 [HO2S2 (B1) signal] or 55 [HO2S2 (B2) signal] and
ground.

6.

Check the voltage when revving up to 4,000 rpm under no load
at least 10 times.
(Depress and release accelerator pedal as soon as possible.)
A change of voltage should be more than 0.12V for 1 sec-
ond during this procedure.
If the voltage can be confirmed in step 6, step 7 is not nec-
essary.

7.

Keep vehicle at idling for 10 minutes, then check the voltage. Or
check the voltage when coasting from 80 km/h (50 MPH) in D
position.
A change of voltage should be more than 0.12V for 1 sec-
ond during this procedure.

8.

If NG, go to 

EC-270, "Diagnosis Procedure"

.

PBIB1607E

DTC P0139, P0159 HO2S2

EC-267

< SERVICE INFORMATION >

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Wiring Diagram

INFOID:0000000001326097

BANK 1

Specification data are reference values and are measured between each terminal and ground.

CAUTION:

Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.

TBWM1592E

EC-268

< SERVICE INFORMATION >

[VQ35DE]

DTC P0139, P0159 HO2S2

TER-

MI-

NAL 

NO.

WIRE 

COLOR

ITEM

CONDITION

DATA (DC Voltage)

25

P

Heated oxygen sensor 2 
heater (bank 1)

[Engine is running]
• Engine speed: Below 3,600 rpm after the fol-

lowing conditions are met

- Engine: After warming up
- Keeping the engine speed between 3,500 

and 4,000 rpm for 1 minute and at idle for 1 
minute under no load

0 - 1.0V

[Ignition switch: ON]
• Engine stopped
[Engine is running]
• Engine speed: Above 3,600 rpm

BATTERY VOLTAGE
(11 - 14V)

74

LG/B

Heated oxygen sensor 2 
(bank 1)

[Engine is running]
• Revving engine from idle to 3,000 rpm quick-

ly after the following conditions are met

- Engine: After warming up
- Keeping the engine speed between 3,500 

and 4,000 rpm for 1 minute and at idle for 1 
minute under no load

0 - Approximately 1.0V

78

B/R

Sensor ground
(Heated oxygen sensor)

[Engine is running]
• Warm-up condition
• Idle speed

Approximately 0V

 

 

 

 

 

 

 

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