NISSAN X-TRAIL 2001 Service Repair Manual

DTC P0138 HO2S2
EC-191
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EC
Removal and InstallationEBS00M4B
HEATED OXYGEN SENSOR 2
Refer to EX-2, "EXHAUST SYSTEM" .

EC-192
[QR25(WITH EURO-OBD)]
DTC P0139 HO2S2
DTC P0139 HO2S2
PFP:226A0
Component DescriptionEBS00M4C
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
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 ModeEBS00M4D
Specification data are reference values.
ECM Terminals and Reference ValueEBS00M4E
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.
On Board Diagnosis LogicEBS00M4F
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 before 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)
●Engine: After warming up
●Keeping the engine speed at
between 3,500 to 4,000 rpm for
one minute and at idle for one
minute under no loadRevving engine from idle up to 3,000
rpm quickly.0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)
●Engine: After warming up
●Keeping the engine speed at
between 3,500 to 4,000 rpm for
one minute and at idle for one
minute under no loadRevving engine from idle up to 3,000
rpm quickly.LEAN ←→ RICH
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
95 OR/BHeated oxygen sen-
sor 2[Engine is running]
●Warm-up condition
●Revving engine from idle up to 3,000 rpm quickly
after the following conditions are met.
●Keeping the engine speed between 3,500 and
4,000 rpm for one minute and at idle for one
minute under no load.0 - Approximately 1.0V
SEF302U

DTC P0139 HO2S2
EC-193
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DTC Confirmation ProcedureEBS00M4G
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.
TESTING CONDITION:
For the best results, perform “DTC WORK SUPPORT” at a temperature of 0 to 30°C (32 to 86°F).
Open engine hood before conducting following procedure.
WITH CONSULT-II
1. Start engine and warm it up to 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 lest one minute under no
load.
4. Let engine idle for one minute.
5. Select “HO2S2 (B1) P0139” of “HO2S2” in “DTC WORK SUPPORT” mode with CONSULT-II and follow
the instruction of CONSULT-II.
6. Make sure that “OK” is displayed after touching “SELF-DIAG RESULTS”.
If “NG” is displayed, refer to EC-196, "
Diagnostic 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. Turn ignition switch “ON” and select “COOLANTEMP/S” in “DATA MONITOR” mode with CONSULT-II.
c. Start engine and warm it up while monitoring “COOLANTEMP/S” indication on CONSULT-II.
d. When “COOLANTEMP/S” indication reaches to 70°C (158°F), go to step 3.
Overall Function CheckEBS00M4H
Use this procedure to check the overall function of the heated oxygen sensor 2 circuit. During this check, a
DTC might not be confirmed.
CAUTION:
Always drive vehicle at a safe speed.
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 one minute under no
load.
4. Let engine idle for one minute.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139
0139Heated oxygen sensor
2 circuit slow responseIt 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
●Injectors
●Intake air leaks
PBIB0115E

EC-194
[QR25(WITH EURO-OBD)]
DTC P0139 HO2S2
5. Set voltmeter probes between ECM terminal 95 (HO2S2 signal) and engine 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 0.06V 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 with “OD” OFF (A/T), 3rd gear position (M/T).
A change of voltage should be more than 0.06V for 1 sec-
ond during this procedure.
8. If NG, go to EC-196, "
Diagnostic Procedure" .
PBIB0550E

DTC P0139 HO2S2
EC-195
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Wiring DiagramEBS00M4I
TBWA0061E

EC-196
[QR25(WITH EURO-OBD)]
DTC P0139 HO2S2
Diagnostic Procedure
EBS00M4J
1. RETIGHTEN GROUND SCREWS
1. Turn ignition switch “OFF”.
2. Loosen and retighten engine ground screws.
>> GO TO 2.
2. CLEAR THE SELF-LEARNING DATA
With CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Select “SELF-LEARNING CONT” in “WORK SUPPORT” mode
with CONSULT-II.
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 or P0172 detected?
Is it difficult to start engine?
Without CONSULT-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch “OFF”.
3. Disconnect mass air flow sensor 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-1142, "
HOW TO ERASE
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 or P0172 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171 or P0172. Refer to EC-200 or EC-206 .
No >> GO TO 3.
PBIB0494E
SEF215Z
PBIB0495E

DTC P0139 HO2S2
EC-197
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3.CHECK HO2S2 GROUND CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch “OFF”.
2. Disconnect heated oxygen sensor 2 harness connector.
3. Check harness continuity between HO2S2 terminal 3 and
engine ground.
Refer to Wiring Diagram.
4. Also check harness for short to power.
OK or NG
OK >> GO TO 4.
NG >> Repair open circuit or short to power in harness or con-
nectors.
4.CHECK HO2S2 INPUT SIGNAL CIRCUIT FOR OPEN AND SHORT
1. Disconnect ECM harness connector.
2. Check harness continuity between ECM terminal 95 and HO2S2 terminal 2.
Refer to Wiring Diagram.
3. Check harness continuity between ECM terminal 95 or HO2S2 terminal 2 and ground.
Refer to Wiring Diagram.
4. Also check harness for short to ground or 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-197, "
Component Inspection" .
OK or NG
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 2.
6.CHECK INTERMITTENT INCIDENT
Refer to EC-115, "
TROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENT" .
>>INSPECTION END
Component InspectionEBS00M4K
HEATED OXYGEN SENSOR 2
With 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 one minute under no
load.
4. Let engine idle for one minute.Continuity should exist.
PBIB0500E
Continuity should exist.
Continuity should not exist.

EC-198
[QR25(WITH EURO-OBD)]
DTC P0139 HO2S2
5. Select “FUEL INJECTION” in “ACTIVE TEST” mode, and select
“HO2S2 (B1)” as the monitor item with CONSULT-II.
6. 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 0.50V 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 one minute under no
load.
4. Let engine idle for one minute.
5. Set voltmeter probes between ECM terminal 95 (HO2S2 signal) and engine 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 0.68V at least once during this
procedure.
If the voltage is above 0.68V at step 4, step 5 is not neces-
sary.
7. Keep vehicle idling for 10 minutes, then check voltage. Or check
the voltage when coasting from 80 km/h (50 MPH) in “D” posi-
tion with “OD” OFF (A/T), 3rd gear position (M/T).
The voltage should be below 0.50V 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.
SEF662Y
PBIB0551E
PBIB0550E

DTC P0139 HO2S2
EC-199
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EC
Removal and InstallationEBS00M4L
HEATED OXYGEN SENSOR 2
Refer to EX-2, "EXHAUST SYSTEM" .

EC-200
[QR25(WITH EURO-OBD)]
DTC P0171 FUEL INJECTION SYSTEM FUNCTION
DTC P0171 FUEL INJECTION SYSTEM FUNCTION
PFP:16600
On Board Diagnosis LogicEBS00M4M
With the Air-Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the
theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensor 1. The
ECM calculates the necessary compensation to correct the offset between the actual and the theoretical
ratios.
In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and light up the MI (2 trip detection logic).
DTC Confirmation ProcedureEBS00M4N
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-II
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch “OFF” and wait at least 10 seconds.
3. Turn ignition switch “ON” and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-II.
4. Clear the self-learning control coefficient by touching “CLEAR”.
5. Select “DATA MONITOR” mode with CONSULT-II.
6. Start engine again and let it idle for at least 10 minutes.
The 1st trip DTC P0171 should be detected at this stage, if a
malfunction exists. If so, go to EC-203, "
Diagnostic Procedure" .
7. If it is difficult to start engine at step 6, the fuel injection system
has a malfunction, too.
8. Crank engine while depressing accelerator pedal. If engine
starts, go to EC-203, "
Diagnostic Procedure" . If engine does not
start, check exhaust and intake air leak visually.
WITH GST
1. Start engine and warm it up to normal operating temperature.
2. Turn ignition switch “OFF” and wait at least 10 seconds.
Sensor Input Signal to ECMECM
functionActuator
Heated oxygen sensors 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injec-
tion controlFuel injectors
DTC No.Trouble diagnosis
nameDTC detecting condition Possible cause
P0171
0171Fuel injection system
too lean
●Fuel injection system does not operate properly.
●The amount of mixture ratio compensation is too
large.
(The mixture ratio is too lean.)
●Intake air leaks
●Heated oxygen sensor 1
●Injectors
●Exhaust gas leaks
●Incorrect fuel pressure
●Lack of fuel
●Mass air flow sensor
●Incorrect PCV hose connection
SEF215Z