2008 INFINITI FX35 sensor

DTC P0138, P0158 HO2S2EC-851
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Removal and InstallationINFOID:0000000001326688
HEATED OXYGEN SENSOR 2
Refer to
EM-179.
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-852
< SERVICE INFORMATION >[VK45DE]
DTC P0139, P0159 HO2S2
DTC P0139, P0159 HO2S2
Component DescriptionINFOID:0000000001326689
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 cont rolled 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 ox ygen sensor 2 is not used for
engine control operation.
CONSULT-III Reference Value in Data Monitor ModeINFOID:0000000001326690
Specification data are reference values.
On Board Diagn osis LogicINFOID:0000000001326691
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the A/F sensor 1. The oxygen 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 s witching response of the sensor's
voltage is faster than specified during the various driving condition
such as fuel-cut.
DTC Confirmation ProcedureINFOID:0000000001326692
NOTE:
If DTC Confirmation Procedure has been previously conduc ted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
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)  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 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
(The sensor circuit is open or shorted)
 Heated oxygen sensor 2
 Fuel pressure
 Fuel injector
 Intake air leaks
P0159
0159
(Bank 2)
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0139, P0159 HO2S2EC-853
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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. Turn ignition switch ON and select “COOLAN TEMP/S” in “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. 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).
7. Select “HO2S2 (B1) P0139” or “HO2S2 (B2) P 0159” 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 display ed after touching “SELF-DIAG RESULTS”.
If “NG” is displayed, refer to EC-857, "
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 CheckINFOID:0000000001326693
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 55 [HO2S2 (B1) signal] or 74 [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-857, "
Diagnosis Procedure".
PBIB2024E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0139, P0159 HO2S2EC-855
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TER-
MI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
6R 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)
55 W/R 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
- After 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 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0139, P0159 HO2S2EC-857
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Diagnosis ProcedureINFOID:0000000001326695
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-723, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CLEAR THE SELF-LEARNING DATA
With CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “W ORK SUPPORT” mode with CONSULT-III.
3. Clear the self-learning control coefficient by touching “CLEAR”.
4. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Without CONSULT-III
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch OFF.
TER-
MI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
25 P Heated oxygen sensor 2
heater (Bank 2) [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 2) [Engine is running]
 Revving engine from idle to 3,000 rpm quick-
ly after the following conditions are met
- Engine: After warming up
- After 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 2) [Engine is running]

Warm-up condition
 Idle speed Approximately 0V
PBIB2195E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-858
< SERVICE INFORMATION >[VK45DE]
DTC P0139, P0159 HO2S2
3. Disconnect mass air flow sensor (1) harness connector, and
restart and run engine for at least 5 seconds at idle speed.
4. Stop engine and reconnect mass air flow sensor harness con-
nector.
5. Make sure DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-633, "
Emission-related
Diagnostic Information".
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed. Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-861 or EC-871.
No >> GO TO 3.
3.CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between HO 2S2 terminal 4 and ECM terminal 78.
Refer to Wiring Diagram.
5. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
4.CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Check harness continuity between ECM terminal and HO2S2 terminal as follows. Refer to Wiring Diagram.
2. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
PBIB3230E
Continuity should exist.
PBIB1534E
DTC Te r m i n a l s
Bank
ECM Sensor
P0139 55 1 1
P0159 74 1 2
Continuity should exist.
DTC Te r m i n a l s
Bank
ECM Sensor
P0139 55 1 1
P0159 74 1 2
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

DTC P0139, P0159 HO2S2EC-859
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3. Also check harness for short to power.
OK or NG
OK >> GO TO 5.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
5.CHECK HEATED OXYGEN SENSOR 2
Refer to EC-859, "
Component Inspection".
OK or NG
OK >> GO TO 6.
NG >> Replace malfunctioning heated oxygen sensor 2.
6.CHECK INTERMITTENT INCIDENT
Refer to EC-717
.
>> INSPECTION END
Component InspectionINFOID:0000000001326696
HEATED OXYGEN SENSOR 2
With CONSULT-III
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. Select “FUEL INJECTION” in “A CTIVE TEST” mode with CONSULT-III, and select “HO2S2 (B1)/(B2)” as
the monitor item.
6. Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to ±25%.
“HO2S2 (B1)/(B2)” should be above 0.78V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)/(B2)” should be below 0.18V at least once when the “FUEL INJECTION” is −25%.
CAUTION:
 Discard any heated oxygen sensor which has been dr opped 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 exh aust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT-III
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 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) signal] and ground.Continuity should not exist.
JMBIA0640GB
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C

EC-860
< SERVICE INFORMATION >[VK45DE]
DTC P0139, P0159 HO2S2
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.)
The voltage should be above 0. 78V at least once during this
procedure.
If the voltage is above 0.78V at step 6, step 7 is not neces-
sary.
7. Keep vehicle at idling for 10 minutes, then check voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D
position.
The voltage should be below 0. 18V at least once during this
procedure.
8. If NG, replace heated oxygen sensor 2.
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 exh aust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Removal and InstallationINFOID:0000000001326697
HEATED OXYGEN SENSOR 2
Refer to EM-179.
PBIB2024E
3AA93ABC3ACD3AC03ACA3AC03AC63AC53A913A773A893A873A873A8E3A773A983AC73AC93AC03AC3
3A893A873A873A8F3A773A9D3AAF3A8A3A8C3A863A9D3AAF3A8B3A8C