2008 NISSAN LATIO engine

EC-248
< SERVICE INFORMATION >
DTC P0138 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 0.18V 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 50 (HO2S2 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 0.68V at least once during this
procedure.
If the voltage is above 0.68V at step 6, step 7 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 position
with OD OFF (A/T), D position (CVT) or 3rd gear position (M/T).
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 exhaust system threads using Oxygen Sensor
Thread Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Removal and InstallationINFOID:0000000001702750
HEATED OXYGEN SENSOR 2
PBIB1783E
PBIB2534E
PBIB2996E

EC-250
< SERVICE INFORMATION >
DTC P0139 HO2S2
DTC P0139 HO2S2
Component DescriptionINFOID:0000000001702751
The heated oxygen sensor 2, after three way catalyst (manifold),
monitors the oxygen level in the exhaust gas.
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-II Reference Value in Data Monitor ModeINFOID:0000000001702752
Specification data are reference values.
On Board Diagnosis LogicINFOID:0000000001702753
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 (manifold) causes
the longer switching time. To judge the malfunctions of heated oxy-
gen sensor 2, ECM monitors whether the switching response of the
sensor's voltage is faster than specified during the various driving
condition such as fuel-cut.
DTC Confirmation ProcedureINFOID:0000000001702754
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
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) • Revving engine from idle to 3,000 rpm quickly after the following condi-
tions are met.
- Engine: After warming up
- Keep the engine speed between 3,500 rpm and 4,000 rpm for 1 minute
and idle for 1 minute under no load0 - 0.3V ←→ Approx. 0.6 - 1.0V
HO2S2 MNTR (B1)LEAN ←→ RICH
SEF302U
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 be-
tween rich and lean than the specified time.• Harness or connectors
(Heated oxygen sensor circuit is open or
shorted.)
• Heated oxygen sensor 2
• Fuel pressure
• Fuel injector
• Intake air leaks

DTC P0139 HO2S2
EC-251
< SERVICE INFORMATION >
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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. 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” of “HO2S2” in “DTC WORK SUPPORT” mode with CONSULT-II.
8. Start engine and following the instruction of CONSULT-II.
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-253, "
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:0000000001702755
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 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 50 (HO2S2 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 0.24V 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), D position (CVT) or 3rd gear posi-
tion (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-253, "
Diagnosis Procedure".
SEF174Y
PBIB2374E
PBIB2996E

DTC P0139 HO2S2
EC-253
< SERVICE INFORMATION >
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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.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis ProcedureINFOID:0000000001702757
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screw on the body.
Refer to EC-142, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
NG >> Repair or replace ground connections.
2.CLEAR THE SELF-LEARNING DATA
With CONSULT-II
TER-
MI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
5GHeated oxygen sensor 2
heater[Engine is running]
• Below 3,600 rpm 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 loadApproximately 10V
[Ignition switch: ON]
• Engine stopped
[Engine is running]
• Engine speed: Above 3,600 rpmBATTERY VOLTAGE
(11 - 14V)
50 W Heated oxygen sensor 2[Engine is running]
• 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 - Approximately 1.0V
59 OSensor ground
(Heated oxygen sensor 2)[Engine is running]
•Warm-up condition
• Idle speedApproximately 0V
PBIA8148J
:Vehicle front
1. Body ground E24 2. Engine ground F9 3. Engine ground F16
4. Body ground E15
BBIA0698E

EC-254
< SERVICE INFORMATION >
DTC P0139 HO2S2
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 (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 that DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-47, "
Emission-related
Diagnostic Information".
7. Make sure that 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-257 or EC-264.
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 (2).
- : Vehicle front
- Heated oxygen sensor 2 (1)
3. Disconnect ECM harness connector.
4. Check harness continuity between HO2S2 terminal 1 and ECM
terminal 59. 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 HO2S2 terminal 4 and ECM terminal 50.
Refer to Wiring Diagram.
2. Check harness continuity between ECM terminal 50 or HO2S2 terminal 4 and ground.
Refer to Wiring Diagram.
3. Also check harness for short to power.
OK or NG
SEF215Z
BBIA0701E
Continuity should exist.
BBIA0700E
Continuity should exist.
Continuity should not exist.

DTC P0139 HO2S2
EC-255
< SERVICE INFORMATION >
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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-255, "
Component Inspection".
OK or NG
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 2.
6.CHECK INTERMITTENT INCIDENT
Refer to EC-136
.
>>INSPECTION END
Component InspectionINFOID:0000000001702758
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 1 minute under no load.
4. Let engine idle for 1 minute.
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 0.18V 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.
SEF662Y
PBIB2534E

EC-256
< SERVICE INFORMATION >
DTC P0139 HO2S2
4. Let engine idle for 1 minute.
5. Set voltmeter probes between ECM terminal 50 (HO2S2 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 0.68V at least once during this
procedure.
If the voltage is above 0.68V at step 6, step 7 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 position
with OD OFF (A/T), D position (CVT) or 3rd gear position (M/T).
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 exhaust system threads using Oxygen Sensor Thread
Cleaner tool J-43897-18 or J-43897-12 and approved anti-seize lubricant.
Removal and InstallationINFOID:0000000001702759
HEATED OXYGEN SENSOR 2
Refer to EM-21
PBIB2996E

DTC P0171 FUEL INJECTION SYSTEM FUNCTION
EC-257
< SERVICE INFORMATION >
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DTC P0171 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001702760
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 air fuel ratio (A/F) 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 lights up the MIL (2 trip detection
logic).
DTC Confirmation ProcedureINFOID:0000000001702761
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-260, "
Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above procedure, perform-
ing the following procedure is advised.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Start engine and drive the vehicle under the similar conditions to
(1st trip) Freeze Frame Data for 10 minutes. Refer to the table
below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Data means the vehicle operation that the following con-
ditions should be satisfied at the same time.
Sensor Input Signal to ECM ECM function Actuator
Air fuel ratio (A/F) sensor 1Density of oxygen in exhaust gas
(Mixture ratio feedback signal)Fuel injection control Fuel injector
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
• Air fuel ratio (A/F) sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection
SEF215Z
Engine speed Engine speed in the freeze frame data ± 400 rpm
Vehicle speed Vehicle speed in the freeze frame data ± 10 km/h (6 MPH)