2010 INFINITI QX56 coolant

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 •
E
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-98
< COMPONENT DIAGNOSIS >[VK56DE]
P0037, P0038, P0057,
P0058 HO2S2 HEATER
P0037, P0038, P0057, P0058 HO2S2 HEATER
DescriptionINFOID:0000000005149100
SYSTEM DESCRIPTION
The ECM performs ON/OFF control of the heated oxy gen sensor 2 heater corresponding to the engine speed,
amount of intake air and engine coolant temperature.
OPERATION
On Board Diagn osis LogicINFOID:0000000005149101
DTC Confirmation ProcedureINFOID:0000000005149102
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 pr ocedure, confirm that battery voltage is between 10.5V and 16V at
idle.
1. Turn ignition switch ON and select “DATA MONITOR” mode with CONSULT-III.
2. Start engine and warm it up to the normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start the engine and keep the engine speed between 3,500 rpm and 4,000 rpm for at least 1 minute under no load.
5. Let engine idle for 1 minute.
Sensor Input signal to ECM ECM function Actuator
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS) Engine speed
Heated oxygen sensor 2
heater controlHeated oxygen sensor 2 heater
Engine coolant temperature sensor Engine coolant temperature
Mass air flow sensor Amount of intake air
Engine speed (rpm) Heated oxygen sensor 2 heater
Above 3,600 OFF
Below 3,600 rpm after the following conditions are met.
• Engine: After warming up
• Keeping the engine speed between 3,500 and 4,000 rpm for 1 minute and at idle for 1 minute under no load ON
DTC No. Trouble diagnosis name
DTC detecting conditionPossible cause
P0037
0037
(Bank 1) Heated oxygen sensor 2
heater control circuit low The current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively low voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.) • Harness or connectors
(The heated oxygen sensor 2 heater
circuit is open or shorted.)
• Heated oxygen sensor 2 heater
P0057
0057
(Bank 2)
P0038
0038
(Bank 1)
Heated oxygen sensor 2
heater control circuit high The current amperage in the heated oxygen sen-
sor 2 heater circuit is out of the normal range.
(An excessively high voltage signal is sent to ECM
through the heated oxygen sensor 2 heater.) • Harness or connectors
(The heated oxygen sensor 2 heater
circuit is shorted.)
• Heated oxygen sensor 2 heater
P0058
0058
(Bank 2)
Revision: April 20092010 QX56

EC-118
< COMPONENT DIAGNOSIS >[VK56DE]
P0116 ECT SENSOR
P0116 ECT SENSOR
Component DescriptionINFOID:0000000005149126
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 elec trical 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 when measuring input/output voltage. Doi ng 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:0000000005149127
NOTE:
If DTC P0116 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117,
P0118. Refer to EC-122, "
DTC Confirmation Procedure".
DTC Confirmation ProcedureINFOID:0000000005149128
NOTE:
If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
• Turn ignition switch OFF and wait at least 10 seconds.
• Turn ignition switch ON.
• Turn ignition switch OFF and wait at least 10 seconds.
TESTING CONDITION:
Before performing the following pro cedure, do not fill with the fuel.
1. Start engine and warm it up to normal operating temperature.
2. Rev engine up to 2,000 rpm for more than10 minutes.
3. Move the vehicle to a cool place, then stop engine and turn ignition switch OFF.
4. Check resistance between “fuel level sensor and fuel pump” terminals 3 and 4.
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 conditionPossible cause
P0116
0116 Engine coolant tempera-
ture sensor circuit range/
performance Engine coolant temperature signal from engine
coolant temperature sensor does not fluctuate,
even when some time has passed after starting
the engine with pre-warming up condition. • Harness or connectors
(High or low resistance in the circuit)
• Engine coolant temperature sensor
Revision: April 20092010 QX56

P0116 ECT SENSOREC-119
< COMPONENT DIAGNOSIS > [VK56DE]
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5. Soak the vehicle until the resistance between “fuel
level sensor and fuel pump” terminals 3 and 4
becomes 0.5 k Ω higher than the value measured before soaking.
CAUTION:
Never turn ignition switch ON during the soaking time.
NOTE:
Soak time changes depending on ambient air temperature. It may take several hours.
6. Start engine and let it idle for 5 minutes.
7. Check 1st trip DTC.
8. If 1st trip DTC is detected, go to EC-119, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149129
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.
NG >> Repair or replace ground connections.
2.CHECK ENGINE COOLANT TEMPERATURE SENSOR
Refer to EC-119, "
Component Inspection".
OK or NG
OK >> GO TO 3.
NG >> Replace engine coolant temperature sensor.
3.CHECK INTERMITTENT INCIDENT
Refer to GI-35, "
How to Check Terminal" and GI-38, "Intermittent Incident".
For Wiring Diagram, refer to EC-435, "
Wiring Diagram - ENGINE CONTROL SYSTEM -".
>> INSPECTION END
Component InspectionINFOID:0000000005149130
ENGINE COOLANT TEMPERATURE SENSOR
1. Check resistance between engine coolant temperature sensor
terminals 1 and 2 as shown in the figure.
BBIA0354E
PBIB2005E
Revision: April 20092010 QX56

EC-120
< COMPONENT DIAGNOSIS >[VK56DE]
P0116 ECT SENSOR
2. If NG, replace engine coolant temperature sensor.
Engine coolant temperature
°C ( °F)] Resistance (kΩ)
20 (68) 2.1 - 2.9
50 (122) 0.68 - 1.00
90 (194) 0.236 - 0.260
SEF012P
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

EC-122
< COMPONENT DIAGNOSIS >[VK56DE]
P0117, P0118 ECT SENSOR
DTC Confirmation Procedure
INFOID:0000000005149133
1. If DTC Confirmation Procedure has been previously conducted, always perform the following procedure
before conducting the next step.
a. Turn ignition switch OFF and wait at least 10 seconds.
b. Turn ignition switch ON.
c. Turn ignition switch OFF and wait at least 10 seconds.
2. Turn ignition switch ON.
3. Wait at least 5 seconds.
4. Check DTC.
5. If DTC is detected, go to EC-122, "
Diagnosis Procedure".
Diagnosis ProcedureINFOID:0000000005149134
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.
NG >> Repair or replace ground connections.
2.CHECK ECT SENSOR POWER SUPPLY CIRCUIT
1. Disconnect engine coolant temperature (ECT) sensor (1) harness connector.
2. Turn ignition switch ON.
BBIA0354E
1. Engine coolant temperature (ETC) sensor 2. Intake manifold
BBIA0775E
Revision: April 20092010 QX56