NISSAN LATIO 2009 Service Repair Manual

EC
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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

YES >> Go to
EC-237, " Diagnosis Procedure " .
NO >> INSPECTION END VHCL SPEED SE 50 - 120 km/h (31 - 75 MPH)

P0172 FUEL INJECTION SYSTEM FUNCTION
EC-237
< COMPONENT DIAGNOSIS >
[HR16DE] C
D E
F
G H
I
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K L
M A EC
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Wiring Diagram
INFOID:0000000004780715
Diagnosis Procedure INFOID:00000000047801381.
CHECK EXHAUST GAS LEAK
1. Start engine and run it at idle. AABWA0309G B

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
< COMPONENT DIAGNOSIS >
[HR16DE] C
D E
F
G H
I
J
K L
M A EC
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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

EC-240< COMPONENT DIAGNOSIS >
[HR16DE]
P0181 FTT SENSOR
P0181 FTT SENSOR
Description INFOID:0000000004780139
The fuel tank temperature sensor is used to detect the fuel tempera-
ture inside the fuel tank. The sensor modifies a voltage signal from
the ECM. The modified signal returns to the ECM as the fuel temper-
ature input. The sensor uses a the rmistor which is sensitive to the
change in temperature. The electric al resistance of the thermistor
decreases as temperature increases.

*: These data are reference values and are measured between ECM terminal 43 (Fuel tank temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output volt age. Doing so may result in damage to the ECM's transis-
tor. Use a ground other than ECM terminals, such as the ground.
DTC Logic INFOID:0000000004780140
DTC DETECTION LOGIC
DTC CONFIRMATION PROCEDURE 1.
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 2. 2.
PERFORM DTC CONFIRMATION PROCEDURE-I
1. Turn ignition switch and wait at least 10 seconds.
2. Check 1st trip DTC.
Is 1st trip DTC detected? YES >> Go to
EC-242, " Diagnosis Procedure " .
NO >> GO TO 3. 3.
CHECK ENGINE COOLANT TEMPERATURE
With CONSULT-III
1. Select “COOLAN TEMP/S” in “DATA MONITOR” mode with CONSULT-III.
2. Check “COOLAN TEMP/S” indication.
With GST
Follow the procedure “With CONSULT-III” above.
Is “ COOLAN TEMP/S ” indication less than 60 ° C (140 ° F)?
YES >> INSPECTION END
NO >> GO TO 4. 4.
PERFORM DTC CONFIRMATION PROCEDURE-IIFluid 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 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
(The sensor circuit is open or shorted)
• Fuel tank temperature sensor

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With CONSULT-III
1. Cool engine down until “COOLAN TE MP/S” indication is less than 60°C (140 °F).
2. Wait at least 10 seconds.
3. Check 1st trip DTC.
With GST
Follow the procedure “With CONSULT-III” above.
Is 1st trip DTC detected? YES >> Go to
EC-242, " Diagnosis Procedure " .
NO >> INSPECTION END

Ground Inspection " .
Is the inspection result normal?

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YES >> GO TO 2.
NO >> Repair or replace ground connection. YES >> GO TO 4.
NO >> GO TO 3. YES >> GO TO 6.
NO >> GO TO 5. Component Inspection " .
Is the inspection result normal? YES >> GO TO 7.
NO >> Replace “fuel level sensor unit and fuel pump”. Diagnosis Procedure " .
Fuel level sensor unit and fuel pump
Ground Voltage
Connector Terminal
B100 4 Ground Approx. 5 V

YES >> INSPECTION END
NO >> Replace “fuel level sensor unit and fuel pump”. Terminals Condition Resistance
4 and 5 Temperature [ °C ( °F)] 20 (68) 2.3 - 2.7 k
Ω
50 (122) 0.79 - 0.90 k Ω