sensor NISSAN LATIO 2009 Service Repair Manual

P0139 HO2S2
EC-221
< COMPONENT DIAGNOSIS >
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P0139 HO2S2
Description INFOID:0000000004780130
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 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 1 V in richer conditions to 0 V in leaner con-
ditions.
Under normal conditions the heated oxygen sensor 2 is not used for
engine control operation.
DTC Logic INFOID:0000000004780131
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 the various driving condi-
tion such as fuel-cut.
DTC CONFIRMATION PROCEDURE 1.
INSPECTION START
Do you have CONSULT-III?
Do you have CONSULT-III? YES >> GO TO 2.
NO >> GO TO 5. 2.
PRECONDITIONING
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.
>> GO TO 3. 3.
PERFORM DTC CONFIRMATION PROCEDURE
With CONSULT-III
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to normal operating temperature. SEF327R
SEF302U
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0139 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

EC-222< COMPONENT DIAGNOSIS >
[HR16DE]
P0139 HO2S2
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. Open engine hood.
6. Select “HO2S2 (B1) P0139” of “HO2S2” in “DTC WORK SUPPORT” mode with CONSULT-III.
7. Follow the instruction of CONSULT-III. NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
8. Touch “SELF-DIAG RESULT”.
Which is displayed on CONSULT-III? OK >> INSPECTION END
NG >> GO TO 4.
CAN NOT BE DIAGNOSED>>GO TO 4. 4.
PERFORM THE RESULT OF DTC CONFIRMATION PROCEDURE
1. Turn ignition switch OFF and leave the vehi cle in a cool place (soak the vehicle).
2. Perform DTC CONFIRMATION PROCEDURE again.
>> GO TO 3. 5.
PERFORM COMPONENT FUNCTION CHECK
Perform component function check. Refer to EC-222, " Component Function Check " .
NOTE:
Use component function check to check the overall func tion of the heated oxygen sensor 2 circuit. During this
check, a 1st trip DTC might not be confirmed.
Is the inspection result normal? YES >> INSPECTION END
NO >> Go to EC-224, " Diagnosis Procedure " .
Component Function Check INFOID:00000000047801321.
PERFORM COMPONENT FUNCTION CHECK-I
Without CONSULT-III
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 least 1 minute under no load.
4. Let engine idle for 1 minute.
5. Check the voltage between ECM harness connector and ground under the following condition.
Is the inspection result normal? YES >> INSPECTION END
NO >> GO TO 2. 2.
PERFORM COMPONENT FUNCTION CHECK-IIECM
Ground Condition Voltage
Con-
nector Terminal
F11 50
(HO2S2
signal) Ground
Revving up to 4,000
rpm under no load at
least 10 times The voltage should be above
0.30 V at least once during
this procedure. PBIB2996E

EC-226< COMPONENT DIAGNOSIS >
[HR16DE]
P0139 HO2S2 6.
REPLACE HEATED OXYGEN SENSOR 2
Replace heated oxygen sensor 2.
CAUTION:
• Discard any sensor which has been dropped from a he ight 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 sensor, clean exhaust system threads usi ng Oxygen Sensor Thread Cleaner
[commercial service tool (J-43897-18 or J43897-12)] and approved Anti-seize Lubricant (commercial
service tool).
>> INSPECTION END 7.
CHECK INTERMITTENT INCIDENT
Refer to EC-120, " Diagnosis Procedure " .
>> INSPECTION END
Component Inspection INFOID:00000000047801341.
INSPECTION START
Do you have CONSULT-III?
Do you have CONSULT-III? YES >> GO TO 2.
NO >> GO TO 3. 2.
CHECK HEATED OXYGEN SENSOR 2
With CONSULT-III
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to 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. Select “FUEL INJECTION” in “ACT IVE TEST” mode, and select “HO2S2 (B1)” as the monitor item with
CONSULT-III.
7. Check “HO2S2 (B1)” at idle speed when adjusting “FUEL INJECTION” to ± 25%.
“HO2S2 (B1)” should be above 0.68 V at l east once when the “FUEL INJECTION” is + 25%.
“HO2S2 (B1)” 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 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. PBIB3458E

P0139 HO2S2
EC-227
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5. Check the voltage between ECM harness connector and ground
under the following condition.
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 and ground
under the following condition.
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 and ground
under the following condition.
Is the inspection result normal? YES >> INSPECTION END
NO >> GO TO 6. 6.
REPLACE HEATED OXYGEN SENSOR 2
Replace heated oxygen sensor 2.
CAUTION:
• Discard any sensor which has been dropped from a he ight of more than 0.5 m (19.7 in) onto a hard
surface such as a concrete floor; use a new one. ECM
Ground Condition Voltage
Con-
nector Termi-
nal
F11 50
(HO2S2 signal) Ground Revving up to 4,000
rpm under no load at
least 10 times The voltage should be
above 0.68 V at least once
during this procedure.
The voltage should be be-
low 0.18 V at least once
during this procedure. PBIB2996E
ECM
Ground Condition Voltage
Con-
nector Termi-
nal
F11 50
(HO2S2 signal) Ground
Keeping engine speed
at idle for 10 minutes The voltage should be
above 0.68 V at least once
during this procedure.
The voltage should be be-
low 0.18 V at least once
during this procedure. JMBIA2199ZZ
ECM
Ground Condition Voltage
Con-
nector Termi-
nal
F11 50
(HO2S2 signal) Ground Coasting from 80 km/h
(50 MPH) in D position
(A/T), 4th gear position
(M/T) The voltage should be
above 0.68 V at least once
during this procedure.
The voltage should be be-
low 0.18 V at least once
during this procedure. JMBIA2200ZZ

EC
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P0171 FUEL INJECTION SYSTEM FUNCTION
DTC Logic INFOID:0000000004780135
DTC DETECTION LOGIC 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 f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extrem ely large (The actual mixture ratio is too lean.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC CONFIRMATION PROCEDURE MIXTURE RATIO SELF-LEARNING VALUE
CLEAR : Special Repair Requirement " .
2. Start engine.
Is it difficult to start engine? YES >> GO TO 3.
NO >> GO TO 4. YES >> Go to
EC-231, " Diagnosis Procedure " .
NO >> Check exhaust and intake air leak visually. YES >> Go to
EC-231, " Diagnosis Procedure " .
NO >> GO TO 5. Sensor Input signal to ECM ECM function Actuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal) Fuel injection control Fuel injectorDTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0171 Fuel 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
• A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection

EC-232< COMPONENT DIAGNOSIS >
[HR16DE]
P0171 FUEL INJECTION SYSTEM FUNCTION
2. Listen for an exhaust gas leak before three way catalyst (manifold).
Is exhaust gas leak detected? YES >> Repair or replace.
NO >> GO TO 2. 2.
CHECK FOR INTAKE AIR LEAK
1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
Intake air leak detected? YES >> Repair or replace.
NO >> GO TO 3. 3.
CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
5. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.
6. Also check harness for short to power.
Is the inspection result normal? YES >> GO TO 4.
NO >> Repair open circuit or short to ground or short to power in harness or connectors. 4.
CHECK FUEL PRESSURE
1. Check fuel pressure. Refer to EC-498, " Inspection " .
Is the inspection result normal? YES >> GO TO 6. PBIB1216E
A/F sensor 1 ECM
Continuity
Connector Terminal Connector Terminal
F12 1
F11 49
Existed
2 53
A/F sensor 1 Ground Continuity
Connector Terminal
F12 1
Ground Not existed
2
ECM Ground Continuity
Connector Terminal
F11 49
Ground Not existed
53

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NO >> GO TO 5. YES >> Replace “fuel filter and fuel pump assembly”.
NO >> Repair or replace Mass Air Flow Sensor " .
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in Service $01 with GST.
3. For specification, refer to EC-504, " Mass Air Flow Sensor " .
Is the measurement value within the specification?YES >> GO TO 7.
NO >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
grounds. Refer to EC-148, " DTC Logic " .
YES >> GO TO 8.
NO >> Perform trouble diagnosis for FUEL INJECTOR, refer to EC-430, " Component Function Check " .
Removal and Installation " .
Keep fuel hose and all fuel injectors connected to fuel tube.
5. Disconnect all ignition coil harness connectors.
6. Prepare pans or saucers under each fuel injector.

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P0172 FUEL INJECTION SYSTEM FUNCTION
DTC Logic INFOID:0000000004780137
DTC DETECTION LOGIC 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 f eedback signal from the A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the of fset between the actual and the theoretical ratios.
In case the amount of the compensation value is extrem ely large (The actual mixture ratio is too rich.), the
ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection logic).
DTC CONFIRMATION PROCEDURE MIXTURE RATIO SELF-LEARNING VALUE
CLEAR : Special Repair Requirement " .
2. Start engine.
Is it difficult to start engine? YES >> GO TO 3.
NO >> GO TO 4. YES >> Go to
EC-237, " Diagnosis Procedure " .
NO >> Check exhaust and intake air leak visually. YES >> Go to
EC-237, " Diagnosis Procedure " .
NO >> GO TO 5. DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0172 Fuel injection system too
rich • Fuel injection system does not operate properly.
• The amount of mixture ratio compensation is too large. (The mixture ratio is too rich.) • A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor

EC-238< COMPONENT DIAGNOSIS >
[HR16DE]
P0172 FUEL INJECTION SYSTEM FUNCTION
2. Listen for an exhaust gas leak before three way catalyst (manifold).
Is exhaust gas leak detected? YES >> Repair or replace.
NO >> GO TO 2. 2.
CHECK FOR INTAKE AIR LEAK
Listen for an intake air leak after the mass air flow sensor.
Is intake air leak detected? YES >> Repair or replace.
NO >> GO TO 3. 3.
CHECK A/F SENSOR 1 INPUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check the continuity between A/F sensor 1 harness connector and ECM harness connector.
5. Check the continuity between A/F sensor 1 harness connector and ground, or ECM harness connector
and ground.
6. Also check harness for short to power.
Is the inspection result normal? YES >> GO TO 4.
NO >> Repair open circuit or short to ground or short to power in harness or connectors. 4.
CHECK FUEL PRESSURE
1. Check fuel pressure. Refer to EC-498, " Inspection " .
Is the inspection result normal? YES >> GO TO 6.
NO >> GO TO 5. PBIB1216E
A/F sensor 1 ECM
Continuity
Connector Terminal Connector Terminal
F12 1
F11 49
Existed
2 53
A/F sensor 1 Ground Continuity
Connector Terminal
F12 1
Ground Not existed
2
ECM Ground Continuity
Connector Terminal
F11 49
Ground Not existed
53

P0172 FUEL INJECTION SYSTEM FUNCTION
EC-239
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DETECT MALFUNCTIONING PART
Check fuel hoses and fuel tubes for clogging.
Is the inspection result normal? YES >> Replace “fuel filter and fuel pump assembly”.
NO >> Repair or replace 6.
CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
3. For specification, refer to EC-504, " Mass Air Flow Sensor " .
With GST
1. Install all removed parts.
2. Check mass air flow sensor signal in “Service $01” with GST.
3. For specification, refer to EC-504, " Mass Air Flow Sensor " .
Is the measurement value within the specification?YES >> GO TO 7.
NO >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
grounds. Refer to EC-148, " DTC Logic " .
7.
CHECK FUNCTION OF FUEL INJECTOR
With CONSULT-III
1. Start engine.
2. Perform “POWER BALANCE” in “A CTIVE TEST” mode with CONSULT-III.
3. Make sure that each circuit produces a momentary engine speed drop.
Without CONSULT-III
1. Let engine idle.
2. Listen to each fuel injector operating sound.
Is the inspection result normal? YES >> GO TO 8.
NO >> Perform trouble diagnosis for FUEL INJECTOR, refer to EC-430, " Component Function Check " .
8.
CHECK FUEL INJECTOR
1. Remove fuel injector assembly. Refer to EM-34, " Removal and Installation " .
Keep fuel hose and all fuel injectors connected to fuel tube.
2. Confirm that the engine is cooled down and t here are no fire hazards near the vehicle.
3. Disconnect all fuel injector harness connectors.
4. Disconnect all ignition coil harness connectors.
5. Prepare pans or saucers under each fuel injectors.
6. Crank engine for about 3 seconds. Make sure fuel does not drip from fuel injector.
Is the inspection result normal? YES >> GO TO 9.
NO >> Replace the fuel injectors from which fuel is dripping. Always replace O-ring with new one. 9.
CHECK INTERMITTENT INCIDENT
Refer to EC-120, " Diagnosis Procedure " .
>> INSPECTION END Clicking noise should be heard.
PBIB3332E