overheating INFINITI QX56 2007 Factory Service Manual

CO-1
ENGINE
C
D
E
F
G
H
I
J
K
L
M
SECTION CO
A
CO
N
O
P
CONTENTS
ENGINE COOLING SYSTEM
SERVICE INFORMATION ............................2
PRECAUTIONS ...................................................2
Precaution for Supplemental Restraint System
(SRS) "AIR BAG" and "SEAT BELT PRE-TEN-
SIONER" ...................................................................
2
Precaution for Liquid Gasket .....................................2
PREPARATION ...................................................4
Special Service Tool .................................................4
Commercial Service Tool ..........................................4
OVERHEATING CAUSE ANALYSIS ..................6
Troubleshooting Chart ...............................................6
COOLING SYSTEM ............................................8
Cooling Circuit ...........................................................8
Schematic .................................................................8
ENGINE COOLANT ............................................9
Inspection ..................................................................9
Changing Engine Coolant .........................................9
RADIATOR ........................................................13
Removal and Installation .........................................13
Checking Radiator ...................................................15
ENGINE COOLING FAN ...................................16
Removal and Installation (Crankshaft Driven
Type) .......................................................................
16
Removal and Installation (Motor Driven Type) ........17
WATER PUMP ..................................................18
Removal and Installation .........................................18
THERMOSTAT AND WATER PIPING ..............20
Removal and Installation .........................................20
SERVICE DATA AND SPECIFICATIONS
(SDS) .................................................................
22
Standard and Limit ..................................................22

CO-6
< SERVICE INFORMATION >
OVERHEATING CAUSE ANALYSIS
OVERHEATING CAUSE ANALYSIS
Troubleshooting ChartINFOID:0000000003531566
Symptom Check items
Cooling sys-
tem parts
malfunctionPoor heat transferWater pump malfunction Worn or loose drive belt
— Thermostat stuck closed —
Damaged finsDust contamination or pa-
per clogging
Physical damage
Clogged radiator cooling
tubeExcess foreign material
(rust, dirt, sand, etc.)
Water cut valve malfunctionExcess foreign material
(rust, dirt, sand, etc.), phys-
ical damage
Reduced air flowCooling fan does not oper-
ate
Fan assembly — High resistance to fan rota-
tion
Damaged fan blades
Damaged radiator shroud — — —
Improper engine coolant
mixture ratio———
Poor engine coolant quality — Engine coolant density —
Insufficient engine coolantEngine coolant leaksCooling hoseLoose clamp
Cracked hose
Water pump Poor sealing
Radiator capLoose
Poor sealing
RadiatorO-ring for damage, deterio-
ration or improper fitting
Cracked radiator tank
Cracked radiator core
Reservoir tank Cracked reservoir tank
Overflowing reservoir tankExhaust gas leaks into cool-
ing systemCylinder head deterioration
Cylinder head gasket deteri-
oration

OVERHEATING CAUSE ANALYSIS
CO-7
< SERVICE INFORMATION >
C
D
E
F
G
H
I
J
K
L
MA
CO
N
P O
Except cool-
ing system
parts mal-
function— Overload on engineAbusive drivingHigh engine rpm under no
load
Driving in low gear for ex-
tended time
Driving at extremely high
speed
Powertrain system malfunc-
tion
— Installed improper size
wheels and tires
Dragging brakes
Improper ignition timing
Blocked or restricted air
flowBlocked bumper —
— Blocked radiator grilleInstalled car brassiere
Mud contamination or paper
clogging
Blocked radiator —
Blocked condenser
Blocked air flow
Installed large fog lamp Symptom Check items

EC-6
DTC P0605 ECM ..............................................444
Component Description .........................................444
On Board Diagnosis Logic .....................................444
DTC Confirmation Procedure ................................444
Diagnosis Procedure .............................................445
DTC P0643 SENSOR POWER SUPPLY ........447
On Board Diagnosis Logic .....................................447
DTC Confirmation Procedure ................................447
Wiring Diagram ......................................................448
Diagnosis Procedure .............................................449
DTC P0850 PNP SWITCH ...............................452
Component Description .........................................452
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
452
On Board Diagnosis Logic .....................................452
DTC Confirmation Procedure ................................452
Overall Function Check .........................................453
Wiring Diagram ......................................................454
Diagnosis Procedure .............................................455
DTC P1140, P1145 IVT CONTROL POSITION
SENSOR ..........................................................
457
Component Description .........................................457
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
457
On Board Diagnosis Logic .....................................457
DTC Confirmation Procedure ................................457
Wiring Diagram ......................................................458
Diagnosis Procedure .............................................461
Component Inspection ...........................................463
Removal and Installation .......................................464
DTC P1148, P1168 CLOSED LOOP CON-
TROL ................................................................
466
On Board Diagnosis Logic .....................................466
DTC P1211 TCS CONTROL UNIT ..................467
Description .............................................................467
On Board Diagnosis Logic .....................................467
DTC Confirmation Procedure ................................467
Diagnosis Procedure .............................................467
DTC P1212 TCS COMMUNICATION LINE .....468
Description .............................................................468
On Board Diagnosis Logic .....................................468
DTC Confirmation Procedure ................................468
Diagnosis Procedure .............................................468
DTC P1217 ENGINE OVER TEMPERATURE .469
Description .............................................................469
CONSULT-II Reference Value in Data Monitor
Mode ......................................................................
469
On Board Diagnosis Logic .....................................470
Overall Function Check .........................................470
Wiring Diagram ......................................................472
Diagnosis Procedure .............................................473
Main 13 Causes of Overheating ............................476
Component Inspection ...........................................476
DTC P1225 TP SENSOR ..................................477
Component Description ........................................477
On Board Diagnosis Logic ....................................477
DTC Confirmation Procedure ................................477
Diagnosis Procedure .............................................477
Removal and Installation .......................................478
DTC P1226 TP SENSOR ..................................479
Component Description ........................................479
On Board Diagnosis Logic ....................................479
DTC Confirmation Procedure ................................479
Diagnosis Procedure .............................................479
Removal and Installation .......................................480
DTC P1421 COLD START CONTROL ............481
Description ............................................................481
On Board Diagnosis Logic ....................................481
DTC Confirmation Procedure ................................481
Diagnosis Procedure .............................................481
DTC P1550 BATTERY CURRENT SENSOR ...483
Component Description ........................................483
CONSULT-II Reference Value in Data Monitor
Mode .....................................................................
483
On Board Diagnosis Logic ....................................483
DTC Confirmation Procedure ................................483
Wiring Diagram .....................................................485
Diagnosis Procedure .............................................486
Component Inspection ..........................................488
DTC P1551, P1552 BATTERY CURRENT
SENSOR ...........................................................
489
Component Description ........................................489
CONSULT-II Reference Value in Data Monitor
Mode .....................................................................
489
On Board Diagnosis Logic ....................................489
DTC Confirmation Procedure ................................489
Wiring Diagram .....................................................491
Diagnosis Procedure .............................................492
Component Inspection ..........................................494
DTC P1553 BATTERY CURRENT SENSOR ...495
Component Description ........................................495
CONSULT-II Reference Value in Data Monitor
Mode .....................................................................
495
On Board Diagnosis Logic ....................................495
DTC Confirmation Procedure ................................495
Wiring Diagram .....................................................497
Diagnosis Procedure .............................................498
Component Inspection ..........................................500
DTC P1554 BATTERY CURRENT SENSOR ...501
Component Description ........................................501
CONSULT-II Reference Value in Data Monitor
Mode .....................................................................
501
On Board Diagnosis Logic ....................................501
Overall Function Check .........................................501
Wiring Diagram .....................................................503
Diagnosis Procedure .............................................504
Component Inspection ..........................................506

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

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"
AWBIA0529ZZ