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EC-968
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DTC P0138, P0158 HO2S2
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Wiring DiagramABS007LQ
BANK 1
TBWM0230E
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DTC P0138, P0158 HO2S2 EC-969
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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.
TER-
MINAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
55 W/R Heated oxygen sensor 2
(bank 1) [Engine is running]
Warm-up condition
Revving engine from idle to 3,000 rpm
quickly after the following conditions are met
–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) [Engine is running]
Warm-up condition
Idle speed
Approximately 0V
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EC-970
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
BANK 2
TBWM0231E
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![INFINITI FX35 2005 Service Manual DTC P0138, P0158 HO2S2 EC-971
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Specification data are reference values and are measured between each terminal and ground.
C INFINITI FX35 2005 Service Manual DTC P0138, P0158 HO2S2 EC-971
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Specification data are reference values and are measured between each terminal and ground.
C](/manual-img/42/57020/w960_57020-2363.png)
DTC P0138, P0158 HO2S2 EC-971
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Revision: 2005 July 2005 FX
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.
Diagnostic ProcedureABS007LR
1. CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-861, "
Ground Inspection" .
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
TER-
MINAL NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
74 LG/B Heated oxygen sensor 2
(bank 2) [Engine is running]
Warm-up condition
Revving engine from idle to 3,000 rpm
quickly after the following conditions are met
–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) [Engine is running]
Warm-up condition
Idle speed
Approximately 0V
PBIB2195E
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![INFINITI FX35 2005 Service Manual EC-972
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
2. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Disconnect heated oxygen sensor 2 harness connector.
2. Disconnect ECM harness INFINITI FX35 2005 Service Manual EC-972
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
2. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Disconnect heated oxygen sensor 2 harness connector.
2. Disconnect ECM harness](/manual-img/42/57020/w960_57020-2364.png)
EC-972
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
2. CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Disconnect heated oxygen sensor 2 harness connector.
2. Disconnect ECM harness connector.
3. Check harness continuity between HO2S2 terminal 4 and ECM terminal 78. Refer to Wiring Diagram.
4. Also check harness for short to ground or short to power.
OK or NG
OK >> GO TO 3.
NG >> Repair open circuit or short to ground or short to power in harness or connectors.
3. 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.
3. Also check harness for 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. Continuity should exist.
PBIB1534E
DTC
Terminals
Bank
ECM Sensor
P0138 55 1 1
P0158 74 1 2
Continuity should exist.
DTC Terminals
Bank
ECM Sensor
P0138 55 1 1
P0158 74 1 2
Continuity should not exist.
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4. CHECK HO2S2 CONNECTOR FOR WATER
Check connectors for water.
OK or NG
OK >> GO TO 5.
NG INFINITI FX35 2005 Service Manual DTC P0138, P0158 HO2S2 EC-973
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4. CHECK HO2S2 CONNECTOR FOR WATER
Check connectors for water.
OK or NG
OK >> GO TO 5.
NG](/manual-img/42/57020/w960_57020-2365.png)
DTC P0138, P0158 HO2S2 EC-973
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4. CHECK HO2S2 CONNECTOR FOR WATER
Check connectors for water.
OK or NG
OK >> GO TO 5.
NG >> Repair or replace harness or connectors.
5. CHECK HEATED OXYGEN SENSOR 2
Refer to EC-973, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace malfunctioning heated oxygen sensor 2.
6. CHECK INTERMITTENT INCIDENT
Refer to EC-854, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>> INSPECTION END
Component InspectionABS007LS
HEATED OXYGEN SENSOR 2
With CONSULT-II
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-II.
2. Start engine and warm it up to the normal operating tempera- ture.
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)/(B2)” as the monitor item with CONSULT-II. Water should not exist.
SEF174Y
SEF662Y
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
7. Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to ±25%.
“HO2S2 (B1)/(B2)” should be above 0.6 INFINITI FX35 2005 Service Manual EC-974
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
7. Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to ±25%.
“HO2S2 (B1)/(B2)” should be above 0.6](/manual-img/42/57020/w960_57020-2366.png)
EC-974
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DTC P0138, P0158 HO2S2
Revision: 2005 July 2005 FX
7. Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to ±25%.
“HO2S2 (B1)/(B2)” should be above 0.62V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)/(B2)” should be below 0.48V at least once when the “FUEL INJECTION” is −25%.
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 tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Without CONSULT-II
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.)
The voltage should be above 0.62V at least once during this
procedure.
If the voltage is above 0.62V 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 0.48V 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 exhaust system threads (using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12) and approved anti-seize lubricant.
Removal and InstallationABS007LT
HEATED OXYGEN SENSOR 2
Refer to EM-182, "EXHAUST MANIFOLD AND THREE WAY CATALYST" .
PBIB1624E
PBIB2024E
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DTC P0139, P0159 HO2S2PFP:226A0
Component DescriptionABS007LU
The heated oxygen sensor 2, aft INFINITI FX35 2005 Service Manual DTC P0139, P0159 HO2S2 EC-975
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DTC P0139, P0159 HO2S2PFP:226A0
Component DescriptionABS007LU
The heated oxygen sensor 2, aft](/manual-img/42/57020/w960_57020-2367.png)
DTC P0139, P0159 HO2S2 EC-975
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DTC P0139, P0159 HO2S2PFP:226A0
Component DescriptionABS007LU
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 heated oxygen sensor 1 are
shifted, the air-fuel ratio is controlled to stoichiometric, by the signal
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-II Reference Value in Data Monitor ModeABS007LV
Specification data are reference values.
On Board Diagnosis LogicABS007LW
The heated oxygen sensor 2 has a much longer switching time
between rich and lean than the heated oxygen 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 switching response of the sen-
sor's voltage is faster than specified during the various driving condi-
tion such as fuel-cut.
SEF327R
MONITOR ITEM CONDITION SPECIFICATION
HO2S2 (B1)
HO2S2 (B2)
Engine: After warming up
After keeping engine speed
between 3,500 and 4,000 rpm for
1 minute and at idle for 1 minute
under no load Revving engine from idle up to 3,000 rpm
quickly. 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
between 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)