2010 INFINITI QX56 light

ON BOARD DIAGNOSTIC (OBD) SYSTEMEC-71
< FUNCTION DIAGNOSIS > [VK56DE]
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*: Leaving cooling fan OFF with CONSULT-III while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to
EC-459, "DTC Index".
SRT WORK SUPPORT Mode
This mode enables a technician to drive a vehicle to set the SRT while monitoring the SRT status.
DTC WORK SUPPORT Mode
TEST ITEM CONDITION JUDGEMENTCHECK ITEM (REMEDY)
FUEL INJEC-
TION • Engine: Return to the original
trouble condition
• Change the amount of fuel injec-
tion using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
• Harness and connectors
• Fuel injector
• Air fuel ratio (A/F) sensor 1
IGNITION TIM-
ING • Engine: Return to the original
trouble condition
• Timing light: Set
• Retard the ignition timing using
CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
• Perform Idle Air Volume Learning.
POWER BAL-
ANCE • Engine: After warming up, idle the
engine.
• A/C switch: OFF
• Selector lever: P or N
• Cut off each injector signal one at a time using CONSULT-III. Engine runs rough or dies.
• Harness and connectors
• Compression
• Fuel injector
• Power transistor
•Spark plug
• Ignition coil
COOLING FAN* • Ignition switch: ON
• Turn the cooling fan HI and OFF
using CONSULT-III. Cooling fan moves and stops. • Harness and connectors
• Cooling fan motor
•IPDM E/R
ENG COOLANT
TEMP • Engine: Return to the original
trouble condition
• Change the engine coolant tem- perature using CONSULT-III. If trouble symptom disappears, see
CHECK ITEM. • Harness and connectors
• Engine coolant temperature sen-
sor
• Fuel injector
FUEL PUMP RE-
LAY • Ignition switch: ON
(Engine stopped)
• Turn the fuel pump relay ON and OFF using CONSULT-III and lis-
ten to operating sound. Fuel pump relay makes the operat-
ing sound.
• Harness and connectors
• Fuel pump relay
PURG VOL
CONT/V • Engine: After warming up, run en-
gine at 1,500 rpm.
• Change the EVAP canister purge
volume control solenoid valve
opening percent using CON-
SULT-III. Engine speed changes according to
the opening percent.
• Harness and connectors
• Solenoid valve
FUEL/T TEMP
SEN • Change the fuel tank temperature using CONSULT-III.
VENT CON-
TROL/V • Ignition switch: ON
(Engine stopped)
• Turn solenoid valve ON and OFF with the CONSULT-III and listen
to operating sound. Solenoid valve makes an operating
sound.
• Harness and connectors
• Solenoid valve
V/T ASSIGN AN-
GLE • Engine: Return to the original
trouble condition
• Change intake valve timing using
CONSULT-III. If trouble symptom disappears, see
CHECK ITEM.
• Harness and connectors
• Intake valve timing control sole-
noid valve
ALTERNATOR
DUTY •
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ngine: Idle
• Change duty ratio using CON- SULT-III. Battery voltage changes. • Harness and connectors
•IPDM E/R
• Alternator
Revision: April 20092010 QX56

EC-74
< COMPONENT DIAGNOSIS >[VK56DE]
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
COMPONENT DIAGNOSIS
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
DescriptionINFOID:0000000005149081
The specification (SP) value indicates the tolerance of
the value that is displayed in “SPEC” of “DATA MONI-
TOR” mode with CONSULT-III during normal operation of the Engine Control System. When the value in
“SPEC” of “DATA MONITOR” mode is within the SP value, the Engine Control System is confirmed OK. When
the value in “SPEC” of “DATA MONITOR” mode is NOT within the SP value, the Engine Control System may
have one or more malfunctions.
The SP value is used to detect malfunctions that may af fect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:
• B/FUEL SCHDL (The fuel injection pulse width progr ammed into ECM prior to any learned on board correc-
tion)
• A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
• MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionINFOID:0000000005149082
• Vehicle driven distance: More than 5,000 km (3,107 miles)
• Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm
2, 14.25 - 15.12 psi)
• Atmospheric temperature: 20 - 30 °C (68 - 86° F)
• Engine coolant temperature: 75 - 95 °C (167 - 203° F)
• Engine speed: Idle
• Transmission: Warmed-up
- After the engine is warmed up to normal operating temper ature, drive vehicle until “ATF TEMP SE 1” (A/T
fluid temperature sensor signal) indicates more than 60 °C (140° F).
• Electrical load: Not applied
- Rear window defogger switch, air conditioner switch, lighting switch are OFF. Steering wheel is straight
ahead.
Inspection ProcedureINFOID:0000000005149083
NOTE:
Perform “SPEC” in “DATA MONITOR” mode in maximum scale display.
1. Perform EC-13, "
Basic Inspection".
2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL”, “A/F ALPHA-B1”, “A/F ALPHA-B2” and “MAS A/F SE-B1” in “SPEC” of “DATA
MONITOR” mode with CONSULT-III.
4. Make sure that monitor items are within the SP value.
5. If NG, go to EC-75, "
Diagnosis Procedure".
Revision: April 20092010 QX56

EC-104
< COMPONENT DIAGNOSIS >[VK56DE]
P0101 MAF SENSOR
P0101 MAF SENSOR
Component DescriptionINFOID:0000000005149110
The mass air flow sensor is placed in the stream of intake air. It mea-
sures the intake flow rate by measuring a part of the entire intake
flow. The mass air flow sensor c
ontrols the temperature of the hot
wire to a certain amount. The heat generated by the hot wire is
reduced as the intake air flows around it. The more air, the greater
the heat loss.
Therefore, the electric current supplied to the hot wire is changed to
maintain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.
On Board Diagn osis LogicINFOID:0000000005149111
DTC Confirmation ProcedureINFOID:0000000005149112
Perform PROCEDURE FOR MALFUNCTION A first.
If the DTC cannot be confirmed, perform PROCEDURE FOR MALFUNCTION B.
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.
PROCEDURE FOR MALFUNCTION A
NOTE:
If engine will not start or stops soon, wait at leas t 10 seconds with engine stopped (Ignition switch ON) instead
of running engine at idle speed.
1. Start engine and warm it up to normal operating temperature.
2. Run engine for at least 10 seconds at idle speed.
3. Check 1st trip DTC.
4. If 1st trip DTC is detected, go to EC-106, "
Diagnosis Procedure".
PROCEDURE FOR MALFUNCTION B
CAUTION:
Always drive vehicle at a safe speed.
With CONSULT-III
BBIA0355E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0101
0101 Mass air flow sensor circuit
range/performance A)
A high voltage from the sensor is sent to ECM
under light load driving condition. • Harness or connectors
(The sensor circuit is open or
shorted.)
• Mass air flow sensor
• EVAP control system pressure sensor
• Intake air temperature sensor
B) A low voltage from the sensor is sent to ECM
under heavy load driving condition. • Harness or connectors
(The sensor circuit is open or
shorted.)
• Intake air leaks
• Mass air flow sensor
• EVAP control system pressure sensor
• Intake air temperature sensor
Revision: April 20092010 QX56

EC-110
< COMPONENT DIAGNOSIS >[VK56DE]
P0102, P0103 MAF SENSOR
P0102, P0103 MAF SENSOR
Component DescriptionINFOID:0000000005149116
The mass air flow sensor is placed in the stream of intake air. It mea-
sures the intake flow rate by measuring a part of the entire intake
flow. The mass air flow sensor c
ontrols the temperature of the hot
wire to a certain amount. The heat generated by the hot wire is
reduced as the intake air flows around it. The more air, the greater
the heat loss.
Therefore, the electric current supplied to the hot wire is changed to
maintain the temperature of the hot wire as air flow increases. The
ECM detects the air flow by means of this current change.
On Board Diagn osis LogicINFOID:0000000005149117
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000005149118
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.
PROCEDURE FOR DTC P0102
1. Start engine and wait at least 5 seconds.
2. Check DTC.
3. If DTC is detected, go to E C - 111 , "
Diagnosis Procedure".
PROCEDURE FOR DTC P0103
1. Turn ignition switch ON.
2. Wait at least 5 seconds.
3. Check DTC.
4. If DTC is detected, go to E C - 111 , "
Diagnosis Procedure".
If DTC is not detected, go to next step.
5. Start engine and wait at least 5 seconds.
6. Check DTC.
7. If DTC is detected, go to E C - 111 , "
Diagnosis Procedure".
BBIA0355E
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0102
0102 Mass air flow sensor circuit
low input An excessively low voltage from the sensor is
sent to ECM. • Harness or connectors
(The sensor circuit is open or shorted.)
• Intake air leaks
• Mass air flow sensor
P0103
0103 Mass air flow sensor circuit
high input An excessively high voltage from the sensor is
sent to ECM. • Harness or connectors
(The sensor circuit is open or shorted.)
• Mass air flow sensor
Detected items Engine operating condition in fail-safe mode
Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
Revision: April 20092010 QX56

P0117, P0118 ECT SENSOREC-121
< COMPONENT DIAGNOSIS > [VK56DE]
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P0117, P0118 ECT SENSOR
Component DescriptionINFOID:0000000005149131
The engine coolant temperature sensor is used to detect the engine
coolant temperature. The sensor
modifies a voltage signal from the
ECM. The modified signal returns to the ECM as the engine coolant
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.

*: This data is reference value and is measured between ECM terminal 73 (Engine
coolant temperature sensor) and ground.
CAUTION:
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.
On Board Diagnosis LogicINFOID:0000000005149132
These self-diagnoses have the one trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode and the MIL lights up.
SEF594K
Engine coolant temperature
°C ( °F)] Voltage* (V)
Resistance (kΩ)
–10 (14) 4.47.0 - 11.4
20 (68) 3.52.1 - 2.9
50 (122) 2.20.68 - 1.00
90 (194) 0.90.236 - 0.260
SEF012P
DTC
No. Trouble Diagnosis Name
DTC Detecting Condition Possible Cause
P0117
0117 Engine coolant temperature
sensor circuit low input An excessively low voltage from the sensor is
sent to ECM.
• Harness or connectors
(The sensor circuit is open or shorted.)
• Engine coolant temperature sensor
P0118
0118 Engine coolant temperature
sensor circuit high input An excessively high voltage from the sensor is
sent to ECM.
Detected items
Engine operating condition in fail-safe mode
Engine coolant temper- ature sensor circuit Engine coolant temperature will be determined by ECM based on the following condition.
CONSULT-III displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-III display)
Just as ignition switch is turned ON or START 40°C (104 °F)
Approx 4 minutes or more after engine starting 80°C (176 °F)
Except as shown above 40 - 80
°C (104 - 176 °F)
(Depends on the time)
When the fail-safe system for engine coolant temperature sensor is activated, the cooling fan operates while
engine is running.
Revision: April 20092010 QX56

P0122, P0123 TP SENSOREC-125
< COMPONENT DIAGNOSIS > [VK56DE]
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P0122, P0123 TP SENSOR
Component DescriptionINFOID:0000000005149136
Electric throttle control actuator
consists of throttle control motor,
throttle position sensor, etc. The throttle position sensor responds to
the throttle valve movement.
The throttle position sensor has t he two sensors. These sensors are
a kind of potentiometers which transform the throttle valve position
into output voltage, and emit the voltage signal to the ECM. In addi-
tion, these sensors detect the opening and closing speed of the
throttle valve and feed the voltage signals to the ECM. The ECM
judges the current opening angle of the throttle valve from these sig-
nals and the ECM controls the throttle control motor to make the
throttle valve opening angle properly in response to driving condi-
tion.
On Board Diagnosis LogicINFOID:0000000005149137
These self-diagnoses have the on e trip detection logic.
FA I L - S A F E M O D E
When the malfunction is detected, ECM ent ers fail-safe mode and the MIL lights up.
DTC Confirmation ProcedureINFOID:0000000005149138
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.
TESTING CONDITION:
Before performing the following procedure, confirm that battery voltage is more than 8V at idle.
1. Start engine and let it idle for 1 second.
2. Check DTC.
3. If DTC is detected, go to EC-125, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149139
1.CHECK GROUND CONNECTIONS
1. Turn ignition switch OFF.
2. Loosen and retighten three ground screws on the body.
PBIB0145E
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0122
0122 Throttle position sensor
2 circuit low input An excessively low voltage from the TP sensor
2 is sent to ECM. • Harness or connectors
(TP sensor 2 circuit is open or shorted.)
(APP sensor 2 circuit is shorted.)
• Electric throttle control actuator
(TP sensor 2)
• Accelerator pedal position sensor (APP sensor 2)
P0123
0123
Throttle position sensor
2 circuit high input An excessively high voltage from the TP sensor
2 is sent to ECM.
Engine operation condition in fail-safe mode
The ECM controls the electric throttle control actuator in regulating the throttle opening in order for the idle position to be within +10
degrees.
The ECM regulates the opening speed of the throttle valve to be slower than the normal condition.
So, the acceleration will be poor.
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

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