2007 INFINITI QX56 engine overheat

EC-92
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
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
Fuel Fuel tank
5
5FL-10
Fuel piping 5 5 5 5 5 5FL-4
Va p o r l o c k—
Valve deposit
5 555 55 5—
Poor fuel (Heavy weight gasoline,
Low octane)—
Air Air duct
55555 5EM-15
Air cleanerEM-15
Air leakage from air duct
(Mass air flow sensor — electric
throttle control actuator)
5555EM-15
Electric throttle control actuatorEM-17
Air leakage from intake manifold/
Collector/GasketEM-17
Cranking Battery
111111
11SC-4
Generator circuitSC-15
Starter circuit 3SC-9
Signal plate 6EM-38
Park/Neutral position (PNP)
switch4AT- 9 9
Engine Cylinder head
55555 55 5EM-64
Cylinder head gasket 4 3
Cylinder block
66666 66 64
EM-78
Piston
Piston ring
Connecting rod
Bearing
Crankshaft
Va l v e
mecha-
nismTiming chain
55555 55 5EM-38
CamshaftEM-46
Intake valve timing controlEM-46
Intake valve
3EM-64
Exhaust valve

TROUBLE DIAGNOSIS
EC-93
< SERVICE INFORMATION >
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1 - 6: The numbers refer to the order of inspection.Exhaust Exhaust manifold/Tube/Muffler/
Gasket
55555 55 5EM-21
, EX-
3Three way catalyst
Lubrica-
tionOil pan/Oil strainer/Oil pump/Oil
filter/Oil gallery/Oil cooler
55555 55 5EM-24
, LU-
14 , LU-11 ,
LU-12
Oil level (Low)/Filthy oilLU-8
Cooling Radiator/Hose/Radiator filler cap
55555 55 45CO-13
Thermostat 5CO-20
Water pumpCO-18
Water galleryCO-8
Cooling fan 5CO-16
Coolant level (Low)/Contaminat-
ed coolant5CO-9
IVIS (INFINITI Vehicle Immobilizer System —
NATS)11BL-116
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

EC-120
< SERVICE INFORMATION >
TROUBLE DIAGNOSIS
*: Leaving cooling fan OFF with CONSULT-II while engine is running may cause the engine to overheat.
DTC & SRT CONFIRMATION MODE
SRT STATUS Mode
For details, refer to EC-49, "Emission-related Diagnostic Information".
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 JUDGEMENT CHECK ITEM (REMEDY)
FUEL INJEC-
TION• Engine: Return to the original
trouble condition
• Change the amount of fuel injec-
tion using CONSULT-II.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-II.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-II.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-II.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-II.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-II 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-II.Engine speed changes according to
the opening percent.• Harness and connectors
• Solenoid valve
FUEL/T TEMP
SEN• Change the fuel tank temperature using CONSULT-II.
VENT CON-
TROL/V• Ignition switch: ON
(Engine stopped)
• Turn solenoid valve ON and OFF
with the CONSULT-II 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-II.If trouble symptom disappears, see
CHECK ITEM.• Harness and connectors
• Intake valve timing control sole-
noid valve
ALTERNATOR
DUTY•Engine: Idle
• Change duty ratio using CON-
SULT-II.Battery voltage changes.• Harness and connectors
• IPDM E/R
•Alternator

DTC P0125 ECT SENSOR
EC-217
< SERVICE INFORMATION >
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DTC P0125 ECT SENSOR
Component DescriptionINFOID:0000000003531719
NOTE:
If DTC P0125 is displayed with P0117 or P0118, first perform the trouble diagnosis for DTC P0117 or
P0118. Refer to EC-205
.
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 when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
On Board Diagnosis LogicINFOID:0000000003531720
DTC Confirmation ProcedureINFOID:0000000003531721
CAUTION:
Be careful not to overheat engine.
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.
WITH CONSULT-II
1. Turn ignition switch ON.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Check that “COOLAN TEMP/S” is above 31°C (88°F).
If it is above 31°C (88°F), the test result will be OK.
If it is below 31°C (88°F), go to following step.
SEF594K
Engine coolant temperature
°C (°F)Voltage* V Resistance kΩ
–10 (14) 4.4 7.0 - 11.4
20 (68) 3.5 2.1 - 2.9
50 (122) 2.2 0.68 - 1.00
90 (194) 0.9 0.236 - 0.260
SEF012P
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0125
0125Insufficient engine coolant
temperature for closed loop
fuel control• Voltage sent to ECM from the sensor is not
practical, even when some time has passed
after starting the engine.
• Engine coolant temperature is insufficient for
closed loop fuel control.• Harness or connectors
(High resistance in the circuit)
• Engine coolant temperature sensor
•Thermostat

EC-470
< SERVICE INFORMATION >
DTC P1217 ENGINE OVER TEMPERATURE
On Board Diagnosis Logic
INFOID:0000000003531991
If the cooling fan or another component in the cooling system malfunctions, engine coolant temperature will
rise.
When the engine coolant temperature reaches an abnormally 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-9, "
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 MA-10, "
SAE Viscosity Number".
2. After refilling coolant, run engine to ensure that no water-flow noise is emitted.
Overall Function CheckINFOID:0000000003531992
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 from 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-II
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-473,
"Diagnosis Procedure".
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-473,
"Diagnosis Procedure".
3. Turn ignition switch ON.
COOLING FAN• Engine: After warming up, idle the
engineEngine coolant temperature: 99°C
(210°F) or lessOFF
Engine coolant temperature: 100°C
(212°F) or moreHI MONITOR ITEM CONDITION SPECIFICATION
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P1217
1217Engine 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 information, refer to EC-476,
"Main 13 Causes of Overheating".
SEF621W

DTC P1217 ENGINE OVER TEMPERATURE
EC-471
< SERVICE INFORMATION >
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4. Perform “COOLING FAN” in “ACTIVE TEST” mode with CON-
SULT-II.
5. If the results are NG, go to EC-473, "
Diagnosis Procedure".
WITH GST
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-473,
"Diagnosis Procedure".
2. Confirm whether customer filled the coolant or not. If customer
filled the coolant, skip the following steps and go to EC-473,
"Diagnosis Procedure".
3. Disconnect engine coolant temperature sensor harness connec-
tor.
4. Connect 150Ω resistor to engine coolant temperature sensor
harness connector.
5. Start engine and make sure that cooling fan operates.
CAUTION:
Be careful not to overheat engine.
6. If NG, go to EC-473, "
Diagnosis Procedure".
SEF646X
SEF621W
SEF882V

EC-474
< SERVICE INFORMATION >
DTC P1217 ENGINE OVER TEMPERATURE
OK (Without CONSULT-II)>>GO TO 3.
NG >> Check cooling fan (crankshaft driven). Refer to CO-16, "
Removal and Installation (Crankshaft
Driven Type)".
2.CHECK COOLING FAN MOTOR OPERATION
With CONSULT-II
1. Start engine and let it idle.
2. Select “COOLING FAN” in “ACTIVE TEST” mode with CON-
SULT-II.
3. Make sure that cooling fan operates.
OK or NG
OK >> GO TO 4.
NG >> Check cooling fan control circuit. (Go to "PROCEDURE
A".)
3.CHECK COOLING FAN MOTOR OPERATION
Without CONSULT-II
1. Disconnect engine coolant temperature sensor harness connector.
2. Connect 150Ω resistor to engine coolant temperature sensor harness connector.
3. Start engine and let it idle.
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-9, "
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-9, "
Inspection".)
• Thermostat. (Refer to CO-20
.)
• Engine coolant temperature sensor. (Refer to EC-209, "
Component Inspection".)
OK or NG
OK >> GO TO 7.
NG >> Replace malfunctioning component.
6.CHECK MAIN 13 CAUSES
If the cause cannot be isolated, go to EC-476, "
Main 13 Causes of Overheating".
SEF646X
SEF882V

EC-476
< SERVICE INFORMATION >
DTC P1217 ENGINE OVER TEMPERATURE
Main 13 Causes of Overheating
INFOID:0000000003531995
*1: Turn the ignition switch ON.
*2: Engine running at 3,000 rpm for 10 minutes.
*3: Drive at 90 km/h (55 MPH) for 30 minutes and then let idle for 10 minutes.
*4: After 60 minutes of cool down time.
For more information, refer to CO-6
.
Component InspectionINFOID:0000000003531996
COOLING FAN MOTOR
1. Disconnect cooling fan motor harness connector.
2. Supply cooling fan motor terminals with battery voltage and
check operation.
Cooling fan motor should operate.
If NG, replace cooling fan motor.
Engine Step Inspection item Equipment Standard Reference page
OFF 1 • Blocked radiator
• Blocked condenser
• Blocked radiator grille
• Blocked bumper• Visual No blocking —
2 • Coolant mixture • Coolant tester 50 - 50% coolant mixtureMA-10
3 • Coolant level • Visual Coolant up to MAX level in
reservoir tank and radiator
filler neckMA-12, "Changing Engine
Coolant"
4 • Reservoir tank cap • Pressure tester 95 - 125 kPa
(0.97 - 1.28 kg/cm2, 14 -
18 psi) (Limit)CO-9, "
Inspection"
ON*25 • Coolant leaks • Visual No leaksCO-9, "Inspection"
ON*26 • Thermostat • Touch the upper and
lower radiator hosesBoth hoses should be hotCO-20
ON*17 • Cooling fan • CONSULT-II Operating See trouble diagnosis for
DTC P1217 (EC-469
).
OFF 8 • Combustion gas leak • Color checker chemical
tester 4 Gas analyzerNegative —
ON*
39 • Coolant temperature
gauge• Visual Gauge less than 3/4 when
driving—
• Coolant overflow to res-
ervoir tank• Visual No overflow during driving
and idlingMA-12, "
Changing Engine
Coolant"
OFF*410 • Coolant return from res-
ervoir tank to radiator• Visual Should be initial level in
reservoir tankMA-12, "Changing Engine
Coolant"
OFF 12 • Cylinder head • Straight gauge feeler
gauge0.1 mm (0.004 in) Maxi-
mum distortion (warping)EM-69, "Inspection After
Disassembly"
13 • Cylinder block and pis-
tons• Visual No scuffing on cylinder
walls or pistonEM-93, "Inspection After
Disassembly"
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