2008 NISSAN LATIO ignition

EC-264
< SERVICE INFORMATION >
DTC P0172 FUEL INJECTION SYSTEM FUNCTION
DTC P0172 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000001702764
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 rich.),
the ECM judges the condition as the fuel injection system malfunction and lights up the MIL (2 trip detection
logic).
DTC Confirmation ProcedureINFOID:0000000001702765
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 P0172 should be detected at this stage, if a
malfunction exists. If so, go to EC-267, "
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
P0172
0172Fuel 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.)• Air fuel ratio (A/F) sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor
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)

DTC P0172 FUEL INJECTION SYSTEM FUNCTION
EC-265
< SERVICE INFORMATION >
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P O7. 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-267, "
Diagnosis Procedure". If engine does not start, remove ignition plugs and
check for fouling, etc.
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 harness con-
nector.
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 P0172 should be
detected at this stage, if a malfunction exists. If so, go to EC-
267, "Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above procedure, 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 Data 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-267, "
Diagnosis Procedure". If engine does not start, remove ignition plugs and
check for fouling, etc.
Engine coolant temperature (T)
conditionWhen 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)
conditionWhen 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 P0172 FUEL INJECTION SYSTEM FUNCTION
EC-267
< 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:0000000001702767
1.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
TERMI-
NAL
NO.WIRE
COLORITEM 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
31V
Y
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LFuel 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
idleBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
•Warm-up condition
• Engine speed: 2,000 rpmBATTERY VOLTAGE
(11 - 14V)
49 W A/F sensor 1[Engine is running]
•Warm-up condition
• Engine speed: 2,000 rpmApproximately 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-268
< SERVICE INFORMATION >
DTC P0172 FUEL INJECTION SYSTEM FUNCTION
Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 3.
NG >> Repair or replace.
3.CHECK AIR FUEL RATIO (A/F) SENSOR 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-78, "
Fuel Pressure Check".
2. Install fuel pressure gauge and check fuel pressure. Refer to EC-78, "
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-526
.)
• Fuel pressure regulator (Refer to EC-78, "
Fuel Pressure Check".)
>> Repair or replace.
6.CHECK MASS AIR FLOW SENSOR
With CONSULT-II
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-II.
With GST
1. Install all removed parts.
2. Start engine and warm it up to normal operating temperature.
3. Check mass air flow sensor signal in Service $01 with GST.
A/F sensor 1 terminal ECM terminal
149
253
Continuity should exist.
Continuity should not exist.
BBIA0699E
At idling: Approximately 350 kPa (3.57 kg/cm2, 51 psi)
at idling : 1.0 - 4.0 g·m/sec
at 2,500 rpm : 2.0 - 10.0 g·m/sec

DTC P0172 FUEL INJECTION SYSTEM FUNCTION
EC-269
< SERVICE INFORMATION >
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P OOK or NG
OK >> GO TO 7.
NG >> Check connectors for rusted terminals or loose connections in the mass air flow sensor circuit or
ground. Refer to EC-167
.
7.CHECK FUNCTION OF FUEL INJECTORS
With CONSULT-II
1. Let engine idle.
2. Perform “POWER BALANCE” in “ACTIVE TEST” mode with
CONSULT-II.
3. Make sure that each circuit produces a momentary engine
speed drop.
Without CONSULT-II
1. Let engine idle.
2. Listen to each fuel injector operating sound.
OK or NG
OK >> GO TO 8.
NG >> Perform trouble diagnosis for EC-521
.
8.CHECK FUEL INJECTOR
1. Remove fuel injector assembly. Refer to EM-33
.
Keep fuel hose and all fuel injector connected to fuel tube.
2. Confirm that the engine is cooled down and there are no fire hazards near the vehicle.
3. Reconnect all harness connectors disconnected.
4. Disconnect all ignition coil harness connectors.
5. Prepare pans or saucers under each fuel injector.
6. Crank engine for about 3 seconds.
Make sure fuel does not drip from fuel injector.
OK or NG
OK (Does not drip.)>>GO TO 9.
NG (Drips.)>>Replace the fuel injectors from which fuel is dripping. Always replace O-ring with new one.
9.CHECK INTERMITTENT INCIDENT
Refer to EC-136
.
>>INSPECTION END at idling : 1.0 - 4.0 g·m/sec
at 2,500 rpm : 2.0 - 10.0 g·m/sec
PBIB0133E
Clicking noise should be heard.
PBIB3332E

EC-270
< SERVICE INFORMATION >
DTC P0181 FTT SENSOR
DTC P0181 FTT SENSOR
Component DescriptionINFOID:0000000001702768
The fuel tank temperature sensor (4) is used to detect the fuel tem-
perature inside the fuel tank. The sensor modifies a voltage signal
from the ECM. The modified signal returns to the ECM as the fuel
temperature input. The sensor uses a thermistor which is sensitive to
the change in temperature. The electrical resistance of the ther-
mistor decreases as temperature increases.
• Fuel level sensor unit and fuel pump (1)
• Fuel pressure regulator (2)
• Fuel level sensor (3)

*: This data is reference values and is measured between ECM terminal 43 (Fuel
tank temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result damage the ECM's transistor. Use
ground other than ECM, such as ground.
On Board Diagnosis LogicINFOID:0000000001702769
DTC Confirmation ProcedureINFOID:0000000001702770
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. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Wait at least 10 seconds.
If the result is NG, go to EC-271, "
Diagnosis Procedure".
If the result is OK, go to following step.
4. Check “COOLAN TEMP/S” value.
If the “COOLAN TEMP/S” is less than 60°C (140°F), the result
will be OK.
If the “COOLAN TEMP/S” is above 60°C (140°F), go to the fol-
lowing step.
5. Cool engine down until “COOLAN TEMP/S” signal is less than
60°C (140°F).
6. Wait at least 10 seconds.
7. If 1st trip DTC is detected, go to EC-271, "
Diagnosis Procedure".
BBIA0704E
Fluid temperature
°C (°F)Voltage*
VResistance
kΩ
20 (68) 3.5 2.3 - 2.7
50 (122) 2.2 0.79 - 0.90
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0181
0181Fuel tank temperature
sensor circuit range/per-
formanceRationally incorrect voltage from the sensor is
sent to ECM, compared with the voltage signals
from engine coolant temperature sensor and in-
take air temperature sensor.• Harness or connectors
(Fuel tank temperature sensor circuit is
open or shorted)
• Fuel tank temperature sensor
SEF174Y

EC-272
< SERVICE INFORMATION >
DTC P0181 FTT SENSOR
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.CHECK FUEL TANK TEMPERATURE SENSOR POWER SUPPLY CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect “fuel level sensor unit and fuel pump” harness con-
nector (1).
- : Vehicle front
3. Turn ignition switch ON.
4. Check voltage between “fuel level sensor unit and fuel pump”
terminal 4 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 4.
NG >> GO TO 3.
3.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors E8, F8
• Harness connectors M69, E7
• Harness connectors B102, M13
• Harness for open or short between ECM and “fuel level sensor unit and fuel pump”
>> Repair open circuit or short to ground or short to power in harness or connector.
4.CHECK FUEL TANK TEMPERATURE SENSOR GROUND CIRCUIT FOR OPEN AND SHORT
:Vehicle front
1. Body ground E24 2. Engine ground F9 3. Engine ground F16
4. Body ground E15
BBIA0698E
BBIA0702E
Voltage: Approximately 5V
PBIB0932E

DTC P0181 FTT SENSOR
EC-273
< SERVICE INFORMATION >
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1. Turn ignition switch OFF.
2. Check harness continuity between “fuel level sensor unit and fuel pump” terminal 5 and combination
meter terminal 24. Refer to Wiring Diagram.
3. Also check harness for short to ground and short to power.
OK or NG
OK >> GO TO 6.
NG >> GO TO 5.
5.DETECT MALFUNCTIONING PART
Check the following.
• Harness connectors B102, M13
• Harness for open or short between “fuel level sensor unit and fuel pump” and ground.
>> Repair open circuit or short to ground or short to power in harness or connectors.
6.CHECK FUEL TANK TEMPERATURE SENSOR
Refer to, EC-273, "
Component Inspection".
OK or NG
OK >> GO TO 7.
NG >> Replace “fuel level sensor unit and fuel pump”.
7.CHECK INTERMITTENT INCIDENT
Perform EC-136
.
>>INSPECTION END
Component InspectionINFOID:0000000001702773
FUEL TANK TEMPERATURE SENSOR
1. Check resistance between “fuel level sensor unit and fuel pump”
terminal 4 and 5 by heating with hot water as shown in the fig-
ure.
2. If NG, replace “fuel level sensor unit and fuel pump”.
Removal and InstallationINFOID:0000000001702774
FUEL TANK TEMPERATURE SENSOR
Refer to FL-5. Continuity should exist.
Temperature °C (°F) Resistance kΩ
20 (68) 2.3 - 2.7
50 (122) 0.79 - 0.90
PBIB0931E