Engine cooling system INFINITI QX56 2008 Factory Owner's Manual

EC-124
< COMPONENT DIAGNOSIS >[VK56DE]
P0117, P0118 ECT SENSOR
P0117, P0118 ECT SENSOR
Component DescriptionINFOID:0000000001351425
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:0000000001351426
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 Na
meDTC Detecting Cond ition 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: March 2010 2008 QX56

EC-280
< COMPONENT DIAGNOSIS >[VK56DE]
P0500 VSS
P0500 VSS
DescriptionINFOID:0000000001351654
NOTE:
•
If DTC P0500 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-87
.
• If DTC P0500 is displayed with DTC U1010, first pe rform the trouble diagnosis for DTC U1010. Refer
to EC-88
.
The vehicle speed signal is sent to the combination meter from the “ABS actuator and electric unit (control
unit)” by CAN communication line. The c combination meter then sends a signal to the ECM by CAN commu-
nication line.
On Board Diagn osis LogicINFOID:0000000001351655
FA I L - S A F E M O D E
When the malfunction is detected, the ECM enters fail-safe mode.
DTC Confirmation ProcedureINFOID:0000000001351656
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Steps 1 and 2 may be conducted with the drive wheels li fted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-III
1. Start engine (VDC switch OFF).
2. Read “VHCL SPEED SE” in “DATA MONITOR” mode with CONSULT-III. The vehicle speed on CON- SULT-III should exceed 10 km/h (6 MPH) when rotating wheels with suitable gear position.
If NG, go to EC-281, "
Diagnosis Procedure".
If OK, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-III.
4. Warm engine up to normal operating temperature.
5. Maintain the following conditions for at least 60 consecutive seconds.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0500
0500 Vehicle speed sensor The almost 0 km/h (0 MPH) signal from
vehicle speed sensor is sent to ECM even
when vehicle is being driven. • Harness or connectors
(The CAN communication line is open or short-
ed)
• Harness or connectors (The vehicle speed signal circuit is open or
shorted)
• Wheel sensor
• Combination meter
• ABS actuator and electric unit (control unit)
Detected items Engine operating condition in fail-safe mode
Vehicle speed sensor When the fail-safe system for vehicle speed sensor is activated, the cooling fan operates (High) while
engine is running.
ENG SPEED
1,600 - 6,000 rpm
COOLAN TEMP/S More than 70°C (158 °F)
B/FUEL SCHDL 6.9 - 31.8 msec
Selector lever Except P or N position
PW/ST SIGNAL OFF
Revision: March 2010 2008 QX56

EC-282
< COMPONENT DIAGNOSIS >[VK56DE]
P0506 ISC SYSTEM
P0506 ISC SYSTEM
DescriptionINFOID:0000000001351659
NOTE:
If DTC P0506 is displayed with ot
her DTC, first perform the trouble diagnosis for the other DTC.
The ECM controls the engine idle speed to a specified leve l through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric thrott le control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idli ng speed. The crankshaft position sensor (POS) detects
the actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration, and engine l oad (air conditioner, power steering and cooling fan
operation, etc.).
On Board Diagn osis LogicINFOID:0000000001351660
DTC Confirmation ProcedureINFOID:0000000001351661
NOTE:
• If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
• If the target idle speed is ou t of the specified value, perform EC-18, "
Idle Air Volume Learning",
before conducting DTC Confirmation Procedur e. For the target idle speed, refer to the EC-503, "
Idle
Speed and Ignition Timing".
TESTING CONDITION:
• Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
• Always perform the test at a temperature above −10° C (14° F).
WITH CONSULT-III
1. Open engine hood.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and run it for at least 1 minute at idle speed.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-282, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351662
1.CHECK INTAKE AIR LEAK
1. Start engine and let it idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 2.
NG >> Discover air leak location and repair.
2.REPLACE ECM
1. Stop engine.
2. Replace ECM.
3. Perform initialization of IVIS(NATS) system and registration of all IVIS(NATS) ignition key IDs. Refer to SEC-8, "
ECM RE-COMMUNICATING FUNCTION : Special Repair Requirement".
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0506
0506 Idle speed control system
RPM lower than expected The idle speed is less than the target idle speed
by 100 rpm or more. • Electric throttle control actuator
• Intake air leak
Revision: March 2010
2008 QX56

EC-284
< COMPONENT DIAGNOSIS >[VK56DE]
P0507 ISC SYSTEM
P0507 ISC SYSTEM
DescriptionINFOID:0000000001351663
NOTE:
If DTC P0507 is displayed with ot
her DTC, first perform the trouble diagnosis for the other DTC.
The ECM controls the engine idle speed to a specified leve l through the fine adjustment of the air, which is let
into the intake manifold, by operating the electric thrott le control actuator. The operating of the throttle valve is
varied to allow for optimum control of the engine idli ng speed. The crankshaft position sensor (POS) detects
the actual engine speed and sends a signal to the ECM.
The ECM controls the electric throttle control actuator so that the engine speed coincides with the target value
memorized in the ECM. The target engine speed is the lowest speed at which the engine can operate steadily.
The optimum value stored in the ECM is determined by taking into consideration various engine conditions,
such as during warming up, deceleration, and engine l oad (air conditioner, power steering and cooling fan
operation, etc.).
On Board Diagn osis LogicINFOID:0000000001351664
DTC Confirmation ProcedureINFOID:0000000001351665
NOTE:
• If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
• If the target idle speed is ou t of the specified value, perform EC-18, "
Idle Air Volume Learning",
before conducting DTC Confirmation Procedur e. For the target idle speed, refer to the EC-503, "
Idle
Speed and Ignition Timing".
TESTING CONDITION:
• Before performing the following procedure, confirm that battery voltage is more than 11V at idle.
• Always perform the test at a temperature above −10° C (14° F).
WITH CONSULT-III
1. Open engine hood.
2. Start engine and warm it up to normal operating temperature.
3. Turn ignition switch OFF and wait at least 10 seconds.
4. Start engine and run it for at least 1 minute at idle speed.
5. Check 1st trip DTC.
6. If 1st trip DTC is detected, go to EC-284, "
Diagnosis Procedure".
WITH GST
Follow the procedure “WITH CONSULT-III” above.
Diagnosis ProcedureINFOID:0000000001351666
1.CHECK PCV HOSE CONNECTION
Confirm that PCV hose is connected correctly.
OK or NG
OK >> GO TO 2.
NG >> Repair or replace.
2.CHECK INTAKE AIR LEAK
1. Start engine and let it idle.
2. Listen for an intake air leak after the mass air flow sensor.
OK or NG
OK >> GO TO 3.
DTC No. Trouble diagnosis name DTC detecting conditionPossible cause
P0507
0507 Idle speed control system
RPM higher than expected The idle speed is more than the target idle
speed by 200 rpm or more. • Electric throttle control actuator
• Intake air leak
• PCV system
Revision: March 2010
2008 QX56

EC-306
< COMPONENT DIAGNOSIS >[VK56DE]
P1217 ENGINE OVER TEMPERATURE
P1217 ENGINE OVER TEMPERATURE
On Board Diagn
osis LogicINFOID:0000000001351714
NOTE:
•If DTC P1217 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-87
.
• If DTC P1217 is displayed with DTC U1010, first pe rform the trouble diagnosis for DTC U1010. Refer
to EC-88
.
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnorma lly high temperature condition, a malfunction is
indicated.
This self-diagnosis has the one trip detection logic.
CAUTION:
When a malfunction is indicated, be sure to replace the coolant. Refer to CO-11, "
Changing Engine
Coolant". Also, replace the engine oil. Refer to LU-9, "Changing Engine Oil".
1. Fill radiator with coolant up to specified level with a filling speed of 2 liters per minute. Be sure to
use coolant with the proper mixture ratio. Refer to CO-10
.
2. After refilling coolant, run engine to en sure that no water-flow noise is emitted.
Overall Function CheckINFOID:0000000001351715
Use this procedure to check the overall function of the cooling fan. During this check, a DTC might not be con-
firmed.
WARNING:
Never remove the radiator cap and/or reservoir tank cap when the engine is hot. Serious burns could
be caused by high pressure fluid escaping fr om the radiator and/or reservoir tank.
Wrap a thick cloth around cap. Carefully remove the cap by turning it a quarter turn to allow built-up
pressure to escape. Then turn the cap all the way off.
WITH CONSULT-III
1. Check the coolant level in the reservoir tank and radiator. Allow engine to cool before checking coolant level.
If the coolant level in the reservoir tank and/or radiator is below
the proper range, skip the following steps and go to EC-395,
"Diagnosis Procedure".
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-395,
"Diagnosis Procedure".
3. Turn ignition switch ON.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1217
1217 Engine over tempera-
ture (Overheat) • Cooling fan does not operate properly (Over-
heat).
• Cooling fan system does not operate proper-
ly (Overheat).
• Engine coolant was not added to the system using the proper filling method.
• Engine coolant is not within the specified range. • Harness or connectors
(The cooling fan circuit is open or short-
ed.)
• Cooling fan
• Cooling fan (crankshaft diven)
• IPDM E/R (Cooling fan relay)
•Radiator hose
•Radiator
•Radiator cap
• Reservoir tank
• Reservoir tank cap
• Water pump
•Thermostat
For more informat ion, refer to EC-308,
"Main 13 Causes of Overheating".
SEF621W
Revision: March 2010 2008 QX56

EC-308
< COMPONENT DIAGNOSIS >[VK56DE]
P1217 ENGINE OVER TEMPERATURE
4. Make sure that cooling fan operates.
OK or NG
OK >> GO TO 4.
NG >> Check cooling fan control circuit. (Go to "PROCEDURE
A".)
4.CHECK COOLING SYSTEM FOR LEAK
Refer to CO-10, "
Inspection".
OK or NG
OK >> GO TO 5.
NG >> Check the following for leak. •Hose
• Radiator
• Radiator cap
• Water pump
• Reservoir tank
5.CHECK COMPONENT PARTS
Check the following.
• RESERVOIR TANK CAP (Refer to CO-10, "
Inspection".)
• Thermostat. (Refer to CO-22, "
Removal and Installation".)
• Engine coolant temperature sensor. (Refer to EC-126, "
Component Inspection".)
OK or NG
OK >> GO TO 6.
NG >> Replace malfunctioning component.
6.CHECK MAIN 13 CAUSES
If the cause cannot be isolated, go to EC-308, "
Main 13 Causes of Overheating".
>> INSPECTION END
Main 13 Causes of OverheatingINFOID:0000000001351718
SEF882V
Engine Step Inspection item EquipmentStandardReference page
OFF 1 • Blocked radiator • Blocked condenser
• Blocked radiator grille
• Blocked bumper • Visual
No blocking —
2 • Coolant mixture • Coolant tester 50 - 50% coolant mixtureCO-10
3 • Coolant level • VisualCoolant up to MAX level in
reservoir tank and radiator
filler neck CO-11, "Changing Engine
Coolant"
4 • Reservoir tank cap • Pre
ssure tester 95 - 125 kPa
(0.97 - 1.28 kg/cm2, 14 -
18 psi) (Limit) CO-10, "
Inspection"
ON*25 • Coolant leaks
• VisualNo leaks CO-10, "Inspection"
ON*26 • Thermostat • Touch the upper and
lower radiator hoses Both hoses should be hot
CO-22, "Removal and In-
stallation"
ON*17 • Cooling fan • CONSULT-IIIOperating See trouble diagnosis for
DTC P1217 ( EC-36
).
Revision: March 2010 2008 QX56

REFRIGERANT PRESSURE SENSOREC-423
< COMPONENT DIAGNOSIS > [VK56DE]
C
D
E
F
G H
I
J
K L
M A
EC
NP
O
REFRIGERANT PRESSURE SENSOR
Component DescriptionINFOID:0000000001365897
The refrigerant pressure sensor is installed at the condenser of the
air conditioner system. The sensor uses an electrostatic volume
pressure transducer to convert refrigerant pressure to voltage. The
voltage signal is sent to ECM, and ECM controls cooling fan system.
Diagnosis ProcedureINFOID:0000000001365899
1.CHECK REFRIGERANT PRESSURE
SENSOR OVERALL FUNCTION
1. Start engine and warm it up to normal operating temperature.
2. Turn A/C switch and blower fan switch ON.
3. Check voltage between ECM terminal 70 and ground with CON- SULT-IIl or tester.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
2.CHECK GROUND CONNECTIONS
1. Turn A/C switch and blower fan switch OFF.
2. Turn ignition switch OFF.
3. Loosen and retighten three ground screws on the body.
BBIA0445E
PBIB2657E
Voltage: 1.0 - 4.0V
PBIB1188E
Revision: March 2010 2008 QX56

EC-460
< ECU DIAGNOSIS >[VK56DE]
ECM
• When there is an open circuit on MIL circuit, the ECM cannot warn the driver by lighting up MIL when there
is malfunction on engine control system.
Therefore, when electrical controlled throttle and pa rt of ECM related diagnoses are continuously detected
as NG for 5 trips, ECM warns the driver that engi ne control system malfunctions and MIL circuit is open by
means of operating fail-safe function.
The fail-safe function also operates when above diagnos es except MIL circuit are detected and demands the
driver to repair the malfunction.
DTC No. Detected items Engine operating condition in fail-safe mode
P0102
P0103 Mass air flow sensor circuit Engine speed will not rise more than 2,400 rpm due to the fuel cut.
P0117
P0118 Engine coolant tempera-
ture sensor circuit Engine coolant temperature will be determined by ECM based on the following condition.
CONSULT-IIl displays the engine coolant temperature decided by ECM.
Condition Engine coolant temperature decided
(CONSULT-IIl display)
Just as ignition switch is turned ON
or START 40
°C (104 °F)
Approx 4 minutes or more after en-
gine 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.
P0122
P0123
P0222
P0223
P2135 Throttle position sensor 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.
P0643 Sensor power supply ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2100
P2103 Throttle control motor relay ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2101 Electric throttle control function ECM stops the electric throttle control actuator control, throttle valve is maintained at a
fixed opening (approx. 5 degrees) by the return spring.
P2118 Throttle control motor ECM stops the electric throttle control actuator control, throttle valve is maintained at a fixed opening (approx. 5 degrees) by the return spring.
P2119 Electric throttle control ac- tuator (When electric throttle control actuator does not function properly due to the return spring
malfunction:)
ECM controls the electric throttle actuator by regulating the throttle opening around the
idle position. The engine speed will not rise more than 2,000 rpm.
(When throttle valve opening angle in fail-safe mode is not in specified range:)
ECM controls the electric throttle control actuator by regulating the throttle opening to 20
degrees or less.
(When ECM detects the throttle valve is stuck open:)
While the vehicle is driving, it slows down gradually by fuel cut. After the vehicle stops, the
engine stalls.
The engine can restart in N or P position, and engine speed will not exceed 1,000 rpm or
more.
P2122
P2123
P2127
P2128
P2138 Accelerator pedal position
sensor
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.
Engine operating condition in fail-safe mode
Engine speed will not rise more than 2,500 rpm due to the fuel cut
Revision: March 2010 2008 QX56

EC-484
< SYMPTOM DIAGNOSIS >[VK56DE]
ENGINE CONTROL SYSTEM SYMPTOMS
1 - 6: The numbers refer to the order of inspection.Exhaust Exhaust manifold/Tube/Muffler/
Gasket 55555 55 5EM-30
,
EX-
5Three way catalyst
Lubrica-
tion Oil pan/Oil strainer/Oil pump/Oil
filter/Oil gallery/Oil cooler
55555 55 5EM-33
,
LU-
14 , LU-11 ,
LU-12
Oil level (Low)/Filthy oil LU-8, "In-
spection"
Cooling Radiator/Hose/Radiator filler cap
55555 55 45 CO-15
Thermostat
5CO-22
Water pump CO-20
Water galleryCO-6
Cooling fan5CO-18,
CO-
19
Coolant level (Low)/Contaminat-
ed coolant 5
CO-10
IVIS (INFINITI Vehicle Immobilizer System —
NATS) 11
SEC-8
SYMPTOM
Reference
page
HARD/NO START/RESTART (EXCP. HA)
ENGINE STALL
HESITATION/SURGING/FLAT SPOT
SPARK KNOCK/DETONATION
LACK OF POWER/POOR ACCELERATION
HIGH IDLE/LOW IDLE
ROUGH IDLE/HUNTING
IDLING VIBRATION
SLOW/NO RETURN TO IDLE
OVERHEATS/WATER TEMPERATURE HIGH
EXCESSIVE FUEL CONSUMPTION
EXCESSIVE OIL CONSUMPTION
BATTERY DEAD (UNDER CHARGE)
Warranty symptom code AA AB AC AD AE AF AG AH AJ AK AL AM HA
Revision: March 2010 2008 QX56

EM-30
< ON-VEHICLE REPAIR >
EXHAUST MANIFOLD AND THREE WAY CATALYST
EXHAUST MANIFOLD AND THREE WAY CATALYST
Exploded ViewINFOID:0000000006055156
Removal and InstallationINFOID:0000000006055157
REMOVAL
WARNING:
Perform the work when the exhaust and cooling system have cooled sufficiently.
1. Remove the engine undercover (rear) using power tool (4WD models).
2. Remove front final drive assembly (4WD models). Refer to DLN-212, "
Removal and Installation".
3. Remove the main muffler assembly and center exhaust tube. Refer to EX-6, "
Removal and Installation".
4. Remove the front exhaust tubes. Refer to EX-6, "
Removal and Installation".
5. Remove front tires. Refer to WT-48, "
Rotation".
6. Remove fender protectors. Refer to EXT-23, "
Removal and Installation".
7. Remove the LH and RH air fuel ratio A/F sensors. • Follow steps below to remove each air fuel ratio A/F sensor.
a. Remove the harness connector of each air fuel ra tio A/F sensor, and harness from bracket and middle
clamp.
1. Air fuel ratio A/F sensor 1 (bank 2) 2. Exhaust manifold cover (bank 2) 3. Exhaust manifold (bank 2)
4. Gaskets 5. Exhaust manifold (bank 1) 6. Exhaust manifold cover (bank 1)
7. Air fuel ratio A/F sensor 1 (bank 1) A. Up B. Coated face
C. Manifold side D. Up mark Front
AWBIA0453GB
Revision: March 2010 2008 QX56