NISSAN LATIO 2009 Service Repair Manual

DTC P0171 FUEL INJECT
ION SYSTEM FUNCTION
EC-745
< SERVICE INFOMATION >
[MR TYPE 1] C
D E
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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.
OK or NG OK >> GO TO 7.
NG >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
ground. Refer to EC-655 .
7.
CHECK FUNCTION OF FUEL INJECTORS
With CONSULT-III
1. Let engine idle.
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.
OK or NG OK >> GO TO 8.
NG >> Perform trouble diagnosis for EC-986 .
8.
CHECK FUEL INJECTOR
1. Confirm that the engine is cooled down and t here are no fire hazards near the vehicle.
2. Turn ignition switch OFF.
3. Reconnect all harness connectors disconnected.
4. Remove fuel tube assembly. Refer to EM-156 .
Keep fuel hose and all fuel injector connected to fuel tube.
The fuel injector harness connectors should remain connected.
5. Disconnect all ignition coil harness connectors.
6. Prepare pans or saucers under each fuel injector.
7. Crank engine for about 3 seconds. Make sure that fuel sprays out from fuel injectors.
OK or NG OK >> GO TO 9.
NG >> Replace fuel injectors from which fuel does not spray out. Always replace O-ring with new ones. 9.
CHECK INTERMITTENT INCIDENT
Refer to EC-626 .
>> INSPECTION END
at idling : 1.0 - 4.0 g·m/sec
at 2,500 rpm : 2.0 - 10.0 g·m/sec Clicking noise should be heard.
PBIB3332E
Fuel should be sprayed evenly
for each fuel injector. PBIA9666J

" 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.
7. If it is difficult to start engine at step 6, the fuel injection system has a malfunction, too.
Sensor Input Signal to ECM ECM function Actuator
Air fuel ratio (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
P0172
0172 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.) • Air fuel ratio (A/F) sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Mass air flow sensor 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 P0172 FUEL INJECT
ION SYSTEM FUNCTION
EC-747
< SERVICE INFOMATION >
[MR TYPE 1] C
D E
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8. Crank engine while depressing accelerator pedal.
If engine starts, go to EC-749, " 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-749, " 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-749, " Diagnosis Procedure " . If engine does not start, remove ignition plugs and
check for fouling, etc. 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).

EC-748< SERVICE INFOMATION >
[MR TYPE 1]
DTC P0172 FUEL INJECTION SYSTEM FUNCTION
Wiring Diagram INFOID:0000000004537230
Specification data are reference values and are measured between each terminal and ground.
Pulse signal is measured by CONSULT-III.
CAUTION: AABWA0326G B

DTC P0172 FUEL INJECT
ION SYSTEM FUNCTION
EC-749
< SERVICE INFOMATION >
[MR TYPE 1] C
D E
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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:00000000045372311.
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
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-750< SERVICE INFOMATION >
[MR TYPE 1]
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) 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 " .)
>> 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
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
1 49
2 53
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 INJECT
ION SYSTEM FUNCTION
EC-751
< SERVICE INFOMATION >
[MR TYPE 1] C
D E
F
G H
I
J
K L
M A EC
NP
O
OK or NG OK >> GO TO 7.
NG >> Check connectors for rusted terminals or loose c onnections in the mass air flow sensor circuit or
ground. Refer to EC-655 .
7.
CHECK FUNCTION OF FUEL INJECTORS
With CONSULT-III
1. Let engine idle.
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.
OK or NG OK >> GO TO 8.
NG >> Perform trouble diagnosis for EC-986 .
8.
CHECK FUEL INJECTOR
1. Remove fuel injector assembly. Refer to EM-156 .
Keep fuel hose and all fuel injector connected to fuel tube.
2. Confirm that the engine is cooled down and t here are no fire hazards near the vehicle.
3. Reconnect all harness connectors disconnected.
4. Disconnect all injector harness connectors.
5. Disconnect all ignition coil harness connectors.
6. Prepare pans or saucers under each fuel injector.
7. 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-626 .
>> INSPECTION END
at idling : 1.0 - 4.0 g·m/sec
at 2,500 rpm : 2.0 - 10.0 g·m/sec Clicking noise should be heard.
PBIB3332E

EC-752< SERVICE INFOMATION >
[MR TYPE 1]
DTC P0181 FTT SENSOR
DTC P0181 FTT SENSOR
Component Description INFOID:0000000004537232
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 elec trical 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 da mage the ECM's transistor. Use
ground other than ECM, such as ground.
On Board Diagn osis Logic INFOID:0000000004537233
DTC Confirmation Procedure INFOID:0000000004537234
NOTE:
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.
WITH CONSULT-III
1. Turn ignition switch ON and wait at least 10 seconds.
2. Check 1st trip DTC. If 1st trip DTC is detected, go to EC-753, " Diagnosis Procedure " .
If 1st trip DTC is not det ected, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-III.
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 following step.
5. Cool engine down until “COOLAN TEMP/S” signal is less than 60 °C (140 °F).
6. Wait at least 10 seconds.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-753, " Diagnosis Procedure " .
WITH GST BBIA0704E
Fluid temperature
°C ( °F) Voltage*
V Resistance
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
0181 Fuel tank temperature
sensor circuit range/per-
formance Rationally 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

DTC P0181 FTT SENSOR
EC-753
< SERVICE INFOMATION >
[MR TYPE 1] C
D E
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M A EC
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Follow the procedure “WITH CONSULT-III” above.
Wiring Diagram INFOID:0000000004537235
Diagnosis Procedure INFOID:00000000045372361.
CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF. BBWA2636E

EC-754< SERVICE INFOMATION >
[MR TYPE 1]
DTC P0181 FTT SENSOR
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.
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-III 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
1. Turn ignition switch OFF. :
Vehicle front
1. Body ground E24 2. Engine ground F9 3. Engine ground F16
4. Body ground E15 BBIA0698E
BBIA0702E
Voltage: Approximately 5V
PBIB0932E