2009 NISSAN LATIO ignition

EC-734< SERVICE INFOMATION >
[MR TYPE 1]
DTC P0139 HO2S2
1. Turn ignition switch ON and select “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. Make sure that “COOLAN TEMP/S” indicates more than 70 °C (158 °F).
If not, warm up engine and go to next step when “C OOLAN TEMP/S” indication reaches to 70°C (158 °F).
7. Select “HO2S2 (B1) P0139” 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-736, " Diagnosis Procedure " .
If “CAN NOT BE DIAG NOSED” is displayed, perform the following.
a. Turn ignition switch OFF and leave the vehi cle in a cool place (soak the vehicle).
b. Return to step 1.
Overall Function Check INFOID:0000000004537219
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 0.24V for 1 sec-
ond during this procedure.
8. If NG, go to EC-736, " Diagnosis Procedure " . PBIB2996E

EC-736< SERVICE INFOMATION >
[MR TYPE 1]
DTC P0139 HO2S2
Do not use ECM ground terminals when measuring in put/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis Procedure INFOID:00000000045372211.
CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten ground screw on the body. Refer to EC-632, " Ground Inspection " .
OK or NG OK >> GO TO 2.
NG >> Repair or replace ground connections. 2.
CLEAR THE SELF-LEARNING DATA
With CONSULT-III
TER-
MI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
5 G Heated 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 load Approximately 10V
[Ignition switch: ON]
• Engine stopped
[Engine is running]
• Engine speed: Above 3,600 rpm BATTERY 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 O Sensor ground
(Heated oxygen sensor 2) [Engine is running]
• Warm-up condition
• Idle speed Approximately 0V PBIA8148J
:
Vehicle front
1. Body ground E24 2. Engine ground F9 3. Engine ground F16
4. Body ground E15 BBIA0698E

DTC P0139 HO2S2
EC-737
< SERVICE INFOMATION >
[MR TYPE 1] C
D E
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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 or P0172 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.
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-542, " 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?
Yes or No Yes >> Perform trouble diagnosis for DTC P0171 or P0172. Refer to
EC-740 or
EC-746 .
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 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-738, " Component Inspection " .
OK or NG BBIA0701E
Continuity should exist.
BBIA0700E
Continuity should exist.
Continuity should not exist.

EC-738< SERVICE INFOMATION >
[MR TYPE 1]
DTC P0139 HO2S2
OK >> GO TO 6.
NG >> Replace heated oxygen sensor 2. 6.
CHECK INTERMITTENT INCIDENT
Refer to EC-626 .
>> INSPECTION END
Component Inspection INFOID:0000000004537222
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 “ACT IVE TEST” mode, and select “HO2S2 (B1)” as the monitor item with
CONSULT-III.
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 thr eads 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 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 and below 0.18V at least
once during this procedure.
If the voltage can be confirmed at step 6, step 7 is not nec-
essary.
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 above 0.68 and below 0.18V at least
once during this procedure. PBIB3458E
PBIB2996E

" Diagnosis Procedure " .
NOTE:
If 1st trip DTC is not detected during above proc edure, performing 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 min- utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta 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 1 Density of oxygen in exhaust gas
(Mixture ratio fe edback signal) Fuel injection control Fuel injectorDTC No.
Trouble diagnosis
name DTC detecting condition Possible cause
P0171
0171 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
• 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 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)

DTC P0171 FUEL INJECT
ION SYSTEM FUNCTION
EC-741
< SERVICE INFOMATION >
[MR TYPE 1] C
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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-743, " Diagnosis Procedure " . If
engine does not start, c heck 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.
3. Disconnect mass air flow sensor (1) harness connector.
4. Restart engine and let idle for at least 5 seconds.
5. Stop engine and reconnect mass air flow sensor (1) harness connector.
6. Select Service $03 with GST. Make sure DTC P0102 is detected.
7. Select Service $04 with GST and erase the DTC P0102.
8. Start engine again and let it idle for at least 10 minutes.
9. Select Service $07 with GST. The 1st trip DTC P0171 should be
detected at this stage, if a malfunction exists. If so, go to EC-743, " Diagnosis Procedure " .
NOTE:
If 1st trip DTC is not detected during above proc edure, performing 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 condi tions to (1st trip) Freeze Frame Data for 10 min-
utes. Refer to the table below.
Hold the accelerator pedal as steady as possible.
The similar conditions to (1st trip) Freeze Frame Da ta means the vehicle operation that the following con-
ditions should be satisfied at the same time.
10. If it is difficult to start engine at step 8, the fuel injection system has a malfunction.
11. Crank engine while depressing accelerator pedal. If engine starts, go to EC-743, " Diagnosis Procedure " .
If engine does not start, check exhaust and intake air leak visually.
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F). BBIA0701E
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)
Engine coolant temperature (T)
condition When the freeze frame data shows lower than 70
°C (158 °F),
T should be lower than 70 °C (158 °F).
When the freeze frame data shows higher than or equal to 70 °C (158 °F),
T should be higher than or equal to 70 °C (158 °F).

DTC P0171 FUEL INJECT
ION SYSTEM FUNCTION
EC-743
< SERVICE INFOMATION >
[MR TYPE 1] C
D E
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G H
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M A EC
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Do not use ECM ground terminals wh
en measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground ot her than ECM terminals, such as the ground.
: Average voltage for pulse signal (Actual pulse signal can be confirmed by oscilloscope.)
Diagnosis Procedure INFOID:00000000045372271.
CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle.
2. Listen for an exhaust gas leak before three way catalyst (manifold).
OK or NG OK >> GO TO 2.
NG >> Repair or replace. 2.
CHECK FOR INTAKE AIR LEAK AND PCV HOSE
TERMI-
NAL
NO. WIRE
COLOR ITEM CONDITION DATA (DC Voltage)
3 G A/F sensor 1 heater [Engine is running]
• Warm-up condition
• Idle speed (More than 140 seconds after starting engine) Approximately 2.9 - 8.8V
25
29
30
31 V
Y
O
L Fuel injector No. 4
Fuel injector No. 3
Fuel injector No. 2
Fuel injector No. 1 [Engine is running]
• Warm-up condition
• Idle speed NOTE:
The pulse cycle changes depending on rpm at
idle BATTERY VOLTAGE
(11 - 14V)
[Engine is running]
• Warm-up condition
• Engine speed: 2,000 rpm BATTERY VOLTAGE
(11 - 14V)
49 W A/F sensor 1 [Engine is running]
• Warm-up condition
• Engine speed: 2,000 rpm Approximately 1.8V
Output voltage varies with air
fuel ratio.
53 B A/F sensor 1 [Ignition switch: ON] Approximately 2.2V PBIA8148J
PBIB0529E
PBIA4943J
PBIB1216E

EC-744< SERVICE INFOMATION >
[MR TYPE 1]
DTC P0171 FUEL INJECTION SYSTEM FUNCTION
1. Listen for an intake air leak after the mass air flow sensor.
2. Check PCV hose connection.
OK or NG OK >> GO TO 3.
NG >> Repair or replace. 3.
CHECK AIR FUEL RATIO (A/F) SENS OR 1 CIRCUIT FOR OPEN AND SHORT
1. Turn ignition switch OFF.
2. Disconnect air fuel ratio (A/F) sensor 1 harness connector (1).
- Air fuel ratio (A/F) sensor 1 (2)
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
5. Check harness continuity between ECM terminals 49, 53 or A/F sensor 1 terminals 1, 2 and ground. Refer to Wiring Diagram.
6. 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. 4.
CHECK FUEL PRESSURE
1. Release fuel pressure to zero. Refer to EC-574, " Fuel Pressure Check " .
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-574, " Fuel Pressure Check " .
OK or NG OK >> GO TO 6.
NG >> GO TO 5. 5.
DETECT MALFUNCTIONING PART
Check the following.
• Fuel pump and circuit (Refer to EC-991 .)
• Fuel pressure regulator (Refer to EC-574, " Fuel Pressure Check " .)
• Fuel lines (Refer to EM-156 .)
• Fuel filter for clogging
>> Repair or replace. 6.
CHECK MASS AIR FLOW SENSOR
With CONSULT-III
1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature.
3. Check “MASS AIR FLOW” in “DATA MONITOR” mode with CONSULT-III.
With GST A/F sensor 1 terminal ECM terminal
1 49
2 53
Continuity should exist.
Continuity should not exist. BBIA0699E
At idling: Approximately 350 kPa (3.57 kg/cm
2
, 51 psi)
at idling : 1.0 - 4.0 g·m/sec
at 2,500 rpm : 2.0 - 10.0 g·m/sec