2010 INFINITI QX56 turn signal

EC-168
< COMPONENT DIAGNOSIS >[VK56DE]
P0139, P0159 HO2S2
If not, warm up engine and go to next step when “C
OOLAN TEMP/S” indication reaches to 70°C (158° F).
7. Open engine hood.
8. Select “HO2S2 (B1) P0139” or “HO2S2 (B2) P0159” of “HO2S2” in “DTC WORK SUPPORT” mode with CONSULT-III.
9. Following the instruction of CONSULT-III. NOTE:
It will take at most 10 minutes until “COMPLETED” is displayed.
10. Make sure that “OK” is display ed after touching “SELF-DIAG RESULTS”.
If “NG” is displayed, refer to EC-168, "
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 CheckINFOID:0000000005149187
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 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 55 [HO2S2 (B1) signal] or 74\
[HO2S2 (B2) 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 0.12 V 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.
A change of voltage should be more than 0.12 V for 1 sec-
ond during this procedure.
8. If NG, go to EC-168, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149188
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body. Refer to EC-85, "
Ground Inspection".
OK or NG
OK >> GO TO 2.
PBIB2054E
BBIA0354E
Revision: April 20092010 QX56

P0139, P0159 HO2S2EC-169
< COMPONENT DIAGNOSIS > [VK56DE]
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NG >> Repair or replace ground connections.
2.CLEAR THE SELF-LEARNING DATA
With CONSULT-III
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, P0172, P0174 or P0175 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 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 DTC P0102 is displayed.
6. Erase the DTC memory. Refer to EC-55, "
Malfunction Indicator
Lamp (MIL)".
7. Make sure DTC P0000 is displayed.
8. Run engine for at least 10 minutes at idle speed.
Is the 1st trip DTC P0171, P0172, P0174 or P0175 detected?
Is it difficult to start engine?
Ye s o r N o
Yes >> Perform trouble diagnosis for DTC P0171, P0174 or P0172, P0175. Refer to EC-172 or EC-177.
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.
3. Disconnect ECM harness connector.
4. Check harness continuity between ECM terminal 78 and HO2S2 terminal 4. 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 ECM terminal and HO2S2 terminal as follows. Refer to Wiring Diagram.
BBIA0368E
Continuity should exist.
BBIA0435E
Revision: April 20092010 QX56

P0139, P0159 HO2S2EC-171
< COMPONENT DIAGNOSIS > [VK56DE]
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7. Check “HO2S2 (B1)/(B2)” at idle speed when adjusting “FUEL INJECTION” to
±25%.
“HO2S2 (B1)/(B2)” should be above 0.58 V at least once when the “FUEL INJECTION” is +25%.
“HO2S2 (B1)/(B2)” should be below 0.18 V at least once when the “FUEL INJECTION” is −25%.
CAUTION:
• Discard any heated oxygen sensor which has been dr opped 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-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 55 [HO2S2 (B1) signal] or 74 [HO2S2 (B2) 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 0.58 V and below 0.18 V at
least once during this procedure.
If the voltage can be confirmed at step 6, step 7 is not nec-
essary.
7. Keep vehicle at idling for 10 minutes, then check voltage. Or check the voltage when coasting from 80 km/h (50 MPH) in D
position.
The voltage should be above 0.58 V and below 0.18 V at
least once during this procedure.
8. If NG, replace heated oxygen sensor 2.
CAUTION:
• Discard any heated oxygen sensor which has been dr opped 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.
JMBIA0605GB
PBIB2054E
Revision: April 20092010 QX56

EC-172
< COMPONENT DIAGNOSIS >[VK56DE]
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
On Board Diagn
osis LogicINFOID:0000000005149190
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 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:0000000005149191
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
WITH CONSULT-III
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.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Turn ignition switch ON and select “SELF-LEARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
6. Clear the self-learning control coefficient by touching “CLEAR”.
7. Start engine. If it is difficult to start engine, the fuel injection system has a malfunction.
Performing the following procedure is advised.
a. Crank engine while depressing accelerator pedal. NOTE:
When depressing accelerator pedal three-fourths (3/4) or more, the control system does not start the
engine. Do not depress accelerator pedal too much.
b. If engine starts, go to EC-173, "
Diagnosis Procedure".
If engine does not start, check exhaus t and intake air leakage visually.
8. Keep engine at idle for least 5 minutes.
9. Check 1st trip DTC.
10. The 1st trip DTC P0171 or P0174 should be detected at this stage, if a malfunction exists. If so, go to EC-
173, "Diagnosis Procedure".
NOTE:
If 1st trip DTC is not detected during above proc edure, performing the following procedure is advised.
SensorInput signal to ECM ECM functionActuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel injection control Fuel injector
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0171
0171
(Bank 1) 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
• A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection
P0174
0174
(Bank 2)
Revision: April 20092010 QX56

EC-174
< COMPONENT DIAGNOSIS >[VK56DE]
P0171, P0174 FUEL INJECTION SYSTEM FUNCTION
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
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 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 harness continuity between the following terminals. Refer to Wiring Diagram.
5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
PBIB1216E
A/F sensor 1 terminal ECM terminal
Bank 1 13
5
25 6
Bank 2 11
6
27 5
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 13 511 6
25 627 5
BBIA0376E
Revision: April 20092010 QX56

P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-177
< COMPONENT DIAGNOSIS > [VK56DE]
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P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
On Board Diagnosis LogicINFOID:0000000005149193
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 A/F sensors 1. The ECM calcu-
lates the necessary compensation to correct the offset 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 ProcedureINFOID:0000000005167701
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
WITH CONSULT-III
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.
4. Turn ignition switch OFF and wait at least 10 seconds.
5. Turn ignition switch ON and select “SELF-LE ARNING CONT” in “WORK SUPPORT” mode with CON-
SULT-III.
6. Clear the self-learning control coefficient by touching “CLEAR”.
7. Start engine. If it is difficult to start engine, the fuel injection system has a malfunction.
Performing the following procedure is advised.
a. Crank engine while depressing accelerator pedal. NOTE:
When depressing accelerator pedal three-fourths (3/4) or more, the control system does not start the
engine. Do not depress accelerator pedal too much.
b. If engine starts, go to EC-178, "
Diagnosis Procedure".
If engine does not start, check exhaust and intake air leakage visually.
8. Keep engine at idle for least 5 minutes.
9. Check 1st trip DTC.
10. The 1st trip DTC P0172 or P0175 should be detected at this stage, if a malfunction exists. If so, go to EC-
173, "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.
Sensor Input signal to ECM ECM functionActuator
A/F sensor 1 Density of oxygen in exhaust gas
(Mixture ratio feedback signal)
Fuel injection control Fuel injector
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0172
0172
(Bank 1) 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
P0175
0175
(Bank 2)
Revision: April 20092010 QX56

P0172, P0175 FUEL INJECTION SYSTEM FUNCTION
EC-179
< COMPONENT DIAGNOSIS > [VK56DE]
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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
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 A/F SENSOR 1 IN PUT SIGNAL CIRCUIT
1. Turn ignition switch OFF.
2. Disconnect corresponding A/F sensor 1 harness connector.
3. Disconnect ECM harness connector.
4. Check harness continuity between the following terminals. Refer to Wiring Diagram.
5. Check harness continuity between the following terminals and ground. Refer to Wiring Diagram.
6. Also check harness for short to power.
PBIB1216E
A/F sensor 1 terminal ECM terminal
Bank 1 13
5
25 6
Bank 2 11
6
27 5
Continuity should exist.
Bank 1 Bank 2
A/F sensor 1 terminal ECM terminal A/F sensor 1 terminal ECM terminal 13 511 6
25 627 5
Continuity should not exist.
BBIA0376E
Revision: April 20092010 QX56

EC-182
< COMPONENT DIAGNOSIS >[VK56DE]
P0181 FTT SENSOR
P0181 FTT SENSOR
Component DescriptionINFOID:0000000005149196
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 electrical resistance of the thermistor
decreases as temperature increases.

*: This data is reference value and is measured between ECM terminal 107 (Fuel
tank temperature sensor) and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output
voltage. Doing so may result in damage to the ECM's transistor.
Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000005149197
DTC Confirmation ProcedureINFOID:0000000005149198
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
1. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Turn ignition switch OFF and wait at least 10 seconds.
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-183, "
Diagnosis Procedure".
If 1st trip DTC is not detected, 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).
BBIA0583E
Fluid temperature
°C ( °F)] Voltage*
(V) Resistance
(kΩ)
20 (68) 3.52.3 - 2.7
50 (122) 2.20.79 - 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
(The sensor circuit is open or shorted)
• Fuel tank temperature sensor
Revision: April 20092010 QX56