2006 INFINITI QX56 check engine

IGNITION SIGNALEC-625
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EC
Revision: November 2009 2006 QX56
3. CHECK OVERALL FUNCTION
Without CONSULT-II
1. Let engine idle.
2. Read the voltage signal between ECM terminals 46, 60, 61, 62, 65, 79, 80, 81 and ground with an oscilloscope.
3. Verify that the oscilloscope screen shows the signal wave as shown below.
NOTE:
The pulse cycle changes depending on rpm at idle.
OK or NG
OK >> INSPECTION END
NG >> GO TO 10.
4. CHECK IGNITION COIL POWER SUPPLY CIRCUIT-I
1. Turn ignition switch OFF, wait at least 10 seconds and then turn ON.
2. Check voltage between ECM terminals 119, 120 and ground with CONSULT-II or tester.
OK or NG
OK >> GO TO 5.
NG >> Go to EC-145, "
POWER SUPPLY AND GROUND CIR-
CUIT" .
PBIB2094E
PBIB0044E
Voltage: Battery voltage
MBIB0034E

IGNITION SIGNALEC-629
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Revision: November 2009 2006 QX56
7. Remove fuel pump fuse in fuse block No. 1 to release fuel pres-
sure.
NOTE:
Do not use CONSULT-II to release fuel pressure, or fuel pres-
sure applies again during the following procedure.
8. Start engine.
9. After engine stalls, crank it two or three times to release all fuel pressure.
10. Turn ignition switch OFF.
11. Remove all ignition coil harness connectors to avoid the electri- cal discharge from the ignition coils.
12. Remove ignition coil and spark plug of the cylinder to be checked.
13. Crank engine for 5 seconds or more to remove combustion gas in the cylinder.
14. Connect spark plug and harness connector to ignition coil.
15. Fix ignition coil using a rope etc. with gap of 13 - 17 mm between the edge of the spark plug and grounded metal portion
as shown in the figure.
16. Crank engine for about 3 seconds, and check whether spark is generated between the spark plug and the grounded metal por-
tion.
CAUTION:

Do not approach to the spark plug and the ignition coil
within 50cm. Be careful not to get an electrical shock
while checking, because the electrical discharge voltage
becomes 20kV or more.

It might cause to damage the ignition coil if the gap of more than 17 mm is taken.
NOTE:
When the gap is less than 13 mm, the spark might be generated even if the coil is malfunctioning.
17. If NG, replace ignition coil with power transistor.
CONDENSER-1
1. Turn ignition switch OFF.
2. Disconnect condenser-1 harness connector.
3. Check resistance between condenser-1 terminals 1 and 2.
Removal and InstallationUBS00L1E
IGNITION COIL WITH POWER TRANSISTOR
Refer to EM-28, "IGNITION COIL" .
Spark should be generated.
BBIA0380E
PBIB2325E
Resistance
Above 1 MΩ at 25 °C (77 °F)
PBIB0794E

EC-632Revision: November 2009
REFRIGERANT PRESSURE SENSOR
2006 QX56
Specification data are reference values and are measured between each terminal 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.
Diagnostic ProcedureUBS00HDJ
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 switch ON.
3. Check voltage between ECM terminal 70 and ground with CON- SULT-II or tester.
OK or NG
OK >> INSPECTION END
NG >> GO TO 2.
2. CHECK GROUND CONNECTIONS
1. Turn A/C switch and blower switch OFF.
2. Turn ignition switch OFF.
3. Loosen and retighten three ground screws on the body. Refer to EC-150, "
Ground Inspection" .
OK or NG
OK >> GO TO 3.
NG >> Repair or replace ground connections.
TER-
MINAL NO. WIRE
COLOR ITEM
CONDITION DATA (DC Voltage)
49 R/Y Sensor power supply
(Refrigerant pressure sen-
sor)
[Ignition switch: ON]
Approximately 5V
67 B Sensor ground [Engine is running]

Warm-up condition

Idle speedApproximately 0V
70 B/W Refrigerant pressure sensor [Engine is running]

Warm-up condition

Both A/C switch and blower switch: ON
(Compressor: Operates)1.0 - 4.0V
Voltage: 1.0 - 4.0V
PBIB1188E
BBIA0354E

EI-6
SQUEAK AND RATTLE TROUBLE DIAGNOSES
Revision: November 20092006 QX56
DUPLICATE THE NOISE AND TEST DRIVE
If possible, drive the vehicle with the customer until the noise is duplicated. Note any additional information on
the Diagnostic Worksheet regarding the conditions or location of the noise. This information can be used to
duplicate the same conditions when you confirm the repair.
If the noise can be duplicated easily during the test drive, to help identify the source of the noise, try to dupli-
cate the noise with the vehicle stopped by doing one or all of the following:
1) Close a door.
2) Tap or push/pull around the area where the noise appears to be coming from.
3) Rev the engine.
4) Use a floor jack to recreate vehicle “twist”.
5) At idle, apply engine load (electrical load, half-clutch on M/T model, drive position on A/T model).
6) Raise the vehicle on a hoist and hit a tire with a rubber hammer.

Drive the vehicle and attempt to duplicate the conditions the customer states exist when the noise occurs.

If it is difficult to duplicate the noise, drive the vehicle slowly on an undulating or rough road to stress the
vehicle body.
CHECK RELATED SERVICE BULLETINS
After verifying the customer concern or symptom, check ASIST for Technical Service Bulletins (TSBs) related
to that concern or symptom.
If a TSB relates to the symptom, follow the procedure to repair the noise.
LOCATE THE NOISE AND IDENTIFY THE ROOT CAUSE
1. Narrow down the noise to a general area.To help pinpoint the source of the noise, use a listening tool (Chassis Ear: J-39570, Engine Ear: J-39565 and mechanic's stethoscope).
2. Narrow down the noise to a more specific area and identify the cause of the noise by:

removing the components in the area that you suspect the noise is coming from.
Do not use too much force when removing clips and fasteners, otherwise clips and fasteners can be bro-
ken or lost during the repair, resulting in the creation of new noise.

tapping or pushing/pulling the component that you suspect is causing the noise.
Do not tap or push/pull the component with excessive force, otherwise the noise will be eliminated only
temporarily.

feeling for a vibration with your hand by touching the component(s) that you suspect is (are) causing the
noise.

placing a piece of paper between components that you suspect are causing the noise.

looking for loose components and contact marks.
Refer to EI-7, "
Generic Squeak and Rattle Troubleshooting" .
REPAIR THE CAUSE

If the cause is a loose component, tighten the component securely.

If the cause is insufficient clearance between components:
–separate components by repositioning or loosening and retightening the component, if possible.
–insulate components with a suitable insulator such as urethane pads, foam blocks, felt cloth tape or ure-
thane tape. A NISSAN Squeak and Rattle Kit (J-43980) is available through your authorized NISSAN
Parts Department.
CAUTION:
Do not use excessive force as many components are constructed of plastic and may be damaged.
Always check with the Parts Department for the latest parts information.
The following materials are contained in the NISSAN Squeak and Rattle Kit (J-43980). Each item can be
ordered separately as needed.
URETHANE PADS [1.5 mm (0.059 in) thick]
Insulates connectors, harness, etc.
76268-9E005: 100× 135 mm (3.94×5.31 in)/76884-71L01: 60 ×85 mm (2.36 ×3.35 in)/76884-71L02: 15 ×25
mm (0.59 ×0.98 in)
INSULATOR (Foam blocks)
Insulates components from contact. Can be used to fill space behind a panel.
73982-9E000: 45 mm (1.77 in) thick, 50 ×50 mm (1.97 ×1.97 in)/73982-50Y00: 10 mm (0.39 in) thick,
50 ×50 mm (1.97 ×1.97 in)
INSULATOR (Light foam block)

EM-1
ENGINE MECHANICAL
B ENGINE
CONTENTS
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SECTION
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EM
Revision: November 2009 2006 QX56
PRECAUTIONS .....................................................
..... 3
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ............................................................. ..... 3
Precautions for Drain Engine Coolant ................. ..... 3
Precautions for Disconnecting Fuel Piping ......... ..... 3
Precautions for Removal and Disassembly ........ ..... 3
Precautions for Inspection, Repair and Replace-
ment .................................................................... ..... 3
Precautions for Assembly and Installation .......... ..... 3
Parts Requiring Angular Tightening .................... ..... 4
Precautions for Liquid Gasket ............................. ..... 4
REMOVAL OF LIQUID GASKET SEALING ..... ..... 4
LIQUID GASKET APPLICATION PROCEDURE ..... 4
PREPARATION ...................................................... ..... 6
Special Service Tools .......................................... ..... 6
Commercial Service Tools ................................... ..... 8
NOISE, VIBRATION, AND HARSHNESS (NVH)
TROUBLESHOOTING ........................................... ... 10
NVH Troubleshooting —Engine Noise ................ ... 10
Use the Chart Below to Help You Find the Cause
of the Symptom. .................................................. .... 11
ENGINE ROOM COVER ....................................... ... 12
Removal and Installation ..................................... ... 12
REMOVAL ........................................................ ... 12
INSTALLATION ................................................ ... 12
DRIVE BELTS ........................................................ ... 13
Checking Drive Belts ........................................... ... 13
DRIVE BELT TENSION ................................... ... 13
Removal and Installation ..................................... ... 13
REMOVAL ........................................................ ... 13
INSTALLATION ................................................ ... 14
Drive Belt Auto Tensioner and Idler Pulley .......... ... 14
REMOVAL ........................................................ ... 14
INSTALLATION ................................................ ... 14
AIR CLEANER AND AIR DUCT ............................ ... 15
Removal and Installation ..................................... ... 15
REMOVAL ........................................................ ... 15INSTALLATION ................................................
... 15
Removal and Installation (Viscous paper type) ... ... 16
REMOVAL ........................................................ ... 16
INSTALLATION ................................................ ... 16
INTAKE MANIFOLD .............................................. ... 17
Removal and Installation ..................................... ... 17
REMOVAL ........................................................ ... 17
INSTALLATION ................................................ ... 19
INSPECTION AFTER INSTALLATION ............. ... 20
EXHAUST MANIFOLD AND THREE WAY CATA-
LYST ....................................................................... ... 21
Removal and Installation ..................................... ... 21
REMOVAL ........................................................ ... 21
INSPECTION AFTER REMOVAL .................... ... 22
INSTALLATION ................................................ ... 22
OIL PAN AND OIL STRAINER .............................. ... 24
Removal and Installation ..................................... ... 24
REMOVAL ........................................................ ... 24
INSPECTION AFTER REMOVAL .................... ... 25
INSTALLATION ................................................ ... 26
INSPECTION AFTER INSTALLATION ............. ... 27
IGNITION COIL ...................................................... ... 28
Removal and Installation ..................................... ... 28
REMOVAL ........................................................ ... 28
INSTALLATION ................................................ ... 28
SPARK PLUG (PLATINUM-TIPPED TYPE) .......... ... 29
Removal and Installation ..................................... ... 29
REMOVAL ........................................................ ... 29
INSPECTION AFTER REMOVAL .................... ... 29
INSTALLATION ................................................ ... 30
FUEL INJECTOR AND FUEL TUBE ..................... ... 31
Removal and Installation ..................................... ... 31
REMOVAL ........................................................ ... 31
INSTALLATION ................................................ ... 32
INSPECTION AFTER INSTALLATION ............. ... 34
ROCKER COVER .................................................. ... 35
Removal and Installation ..................................... ... 35
REMOVAL ........................................................ ... 35
INSTALLATION ................................................ ... 36

EM-2Revision: November 20092006 QX56
TIMING CHAIN .......................................................
... 37
Removal and Installation ..................................... ... 37
REMOVAL ........................................................ ... 38
INSPECTION AFTER REMOVAL ..................... ... 40
INSTALLATION ................................................. ... 41
CAMSHAFT ............................................................ ... 46
Removal and Installation ..................................... ... 46
REMOVAL ........................................................ ... 46
INSPECTION AFTER REMOVAL ..................... ... 50
INSTALLATION ................................................. ... 52
Valve Clearance ................................................... ... 55
INSPECTION .................................................... ... 55
ADJUSTMENT ................................................. ... 58
OIL SEAL ............................................................... ... 60
Removal and Installation of Valve Oil Seal .......... ... 60
REMOVAL ........................................................ ... 60
INSTALLATION ................................................. ... 60
Removal and Installation of Front Oil Seal .......... ... 61
REMOVAL ........................................................ ... 61
INSTALLATION ................................................. ... 61
Removal and Installation of Rear Oil Seal ........... ... 61
REMOVAL ........................................................ ... 61
INSTALLATION ................................................. ... 62
CYLINDER HEAD .................................................. ... 63
On-Vehicle Service .............................................. ... 63
CHECKING COMPRESSION PRESSURE ......... 63
Removal and Installation ..................................... ... 64
REMOVAL ........................................................ ... 64
INSPECTION AFTER REMOVAL ..................... ... 65
INSTALLATION ................................................. ... 65
Disassembly and Assembly ................................. ... 66
DISASSEMBLY ................................................ ... 66
ASSEMBLY ...................................................... ... 67
Inspection After Disassembly .............................. ... 68
CYLINDER HEAD DISTORTION ..................... ... 68
VALVE DIMENSIONS ....................................... ... 69
VALVE GUIDE CLEARANCE ........................... ... 69
VALVE GUIDE REPLACEMENT ...................... ... 70
VALVE SEAT CONTACT .................................. ... 71
VALVE SEAT REPLACEMENT ........................ ... 71
VALVE SPRING SQUARENESS ...................... ... 73
VALVE SPRING DIMENSIONS AND VALVE
SPRING PRESSURE LOAD ............................ ... 73
ENGINE ASSEMBLY ................................................ 74 Removal and Installation ..................................... ... 74
REMOVAL ........................................................ ... 74
INSTALLATION ................................................. ... 76
INSPECTION AFTER INSTALLATION ............. ... 76CYLINDER BLOCK ................................................
... 78
Disassembly and Assembly ................................. ... 78
DISASSEMBLY ................................................. ... 79
ASSEMBLY ....................................................... ... 82
How to Select Piston and Bearing ....................... ... 87
DESCRIPTION ................................................. ... 87
HOW TO SELECT PISTON .............................. ... 87
HOW TO SELECT CONNECTING ROD BEAR-
ING .................................................................... ... 88
HOW TO SELECT MAIN BEARING ................. ... 90
Inspection After Disassembly ............................... ... 94
CRANKSHAFT END PLAY ............................... ... 94
CONNECTING ROD SIDE CLEARANCE ........ ... 94
PISTON AND PISTON PIN CLEARANCE ........ ... 94
PISTON RING SIDE CLEARANCE .................. ... 95
PISTON RING END GAP ................................. ... 95
CONNECTING ROD BEND AND TORSION .... ... 96
CONNECTING ROD BEARING (BIG END) ..... ... 96
CONNECTING ROD BUSHING OIL CLEAR-
ANCE (SMALL END) ........................................ ... 96
CYLINDER BLOCK DISTORTION ................... ... 97
MAIN BEARING HOUSING INSIDE DIAMETER ... 98
PISTON TO CYLINDER BORE CLEARANCE . ... 98
CRANKSHAFT JOURNAL DIAMETER ............ ... 99
CRANKSHAFT PIN DIAMETER ....................... .100
OUT-OF-ROUND AND TAPER OF CRANK-
SHAFT .............................................................. .100
CRANKSHAFT RUNOUT ................................. .100
CONNECTING ROD BEARING OIL CLEAR-
ANCE ................................................................ .100
MAIN BEARING OIL CLEARANCE .................. .101
CRUSH HEIGHT OF MAIN BEARING ............. .102
CRUSH HEIGHT OF CONNECTING ROD
BEARING .......................................................... .102
MAIN BEARING CAP BOLT DIAMETER .......... .102
CONNECTING ROD BOLT DIAMETER ........... .103
SERVICE DATA AND SPECIFICATIONS (SDS) ... .104
Standard and Limit ............................................... .104
GENERAL SPECIFICATIONS .......................... .104
DRIVE BELTS ................................................... .104
EXHAUST MANIFOLD ..................................... .104
CAMSHAFT AND CAMSHAFT BEARING ........ .105
CYLINDER HEAD ............................................. .107
CYLINDER BLOCK ........................................... .109
PISTON, PISTON RING AND PISTON PIN ..... .110
CONNECTING ROD ......................................... .110
CRANKSHAFT .................................................. . 111
MAIN BEARING ................................................ .112

PRECAUTIONSEM-3
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Revision: November 2009 2006 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
EBS00REI
The Supplemental Restraint System such as “AIR BAG” and “SEAT BELT PRE-TENSIONER ”, used along
with a front seat belt, helps to reduce the risk or severity of injury to the driver and front passenger for certain
types of collision. This system includes seat belt switch inputs and dual stage front air bag modules. The SRS
system uses the seat belt switches to determine the front air bag deployment, and may only deploy one front
air bag, depending on the severity of a collision and whether the front occupants are belted or unbelted.
Information necessary to service the system safely is included in the SRS and SB section of this Service Man-
ual.
WARNING:

To avoid rendering the SRS inoperative, which could increase the risk of personal injury or death
in the event of a collision which would result in air bag inflation, all maintenance must be per-
formed by an authorized NISSAN/INFINITI dealer.

Improper maintenance, including incorrect removal and installation of the SRS, can lead to per-
sonal injury caused by unintentional activation of the system. For removal of Spiral Cable and Air
Bag Module, see the SRS section.

Do not use electrical test equipment on any circuit related to the SRS unless instructed to in this
Service Manual. SRS wiring harnesses can be identified by yellow and/or orange harnesses or
harness connectors.
Precautions for Drain Engine CoolantEBS00REJ
Drain engine coolant when engine is cooled.
Precautions for Disconnecting Fuel PipingEBS00REK

Before starting work, make sure no fire or spark producing items are in the work area.

Release fuel pressure before disconnecting and disassembly.

After disconnecting pipes, plug openings to stop fuel leakage.
Precautions for Removal and DisassemblyEBS00REL

When instructed to use special service tools, use the specified tools. Always be careful to work safely,
avoid forceful or uninstructed operations.

Exercise maximum care to avoid damage to mating or sliding surfaces.

Cover openings of engine system with tape or the equivalent, if necessary, to seal out foreign materials.

Mark and arrange disassembly parts in an organized way for easy troubleshooting and assembly.

When loosening nuts and bolts, as a basic rule, start with the one furthest outside, then the one diagonally
opposite, and so on. If the order of loosening is specified, do exactly as specified. Power tools may be
used where noted in the step.
Precautions for Inspection, Repair and ReplacementEBS00REM
Before repairing or replacing, thoroughly inspect parts. Inspect new replacement parts in the same way, and
replace if necessary.
Precautions for Assembly and InstallationEBS00REN

Use torque wrench to tighten bolts or nuts to specification.

When tightening nuts and bolts, as a basic rule, equally tighten in several different steps starting with the
ones in center, then ones on inside and outside diagonally in this order. If the order of tightening is speci-
fied, do exactly as specified.

Replace with new gasket, packing, oil seal or O-ring.

Thoroughly wash, clean, and air-blow each part. Carefully check engine oil or engine coolant passages for
any restriction and blockage.

Avoid damaging sliding or mating surfaces. Completely remove foreign materials such as cloth lint or dust.
Before assembly, oil sliding surfaces well.

Release air within route when refilling after draining engine coolant.

EM-4Revision: November 2009
PRECAUTIONS
2006 QX56

Before starting engine, apply fuel pressure to fuel lines with turning ignition switch ON (with engine
stopped). Then make sure that there are no leaks at fuel line connections.

After repairing, start engine and increase engine speed to check engine coolant, fuel, oil, and exhaust
systems for leakage.
Parts Requiring Angular TighteningEBS00REO

For final tightening of the following engine parts use Tool:
–Cylinder head bolts
–Main bearing cap bolts
–Connecting rod cap bolts
–Crankshaft pulley bolt (No angle wrench is required as the bolt flange is provided with notches for angle
tightening)

Do not use a torque value for final tightening.

The torque value for these parts are for a preliminary step.

Ensure thread and seat surfaces are clean and lightly coated with engine oil.
Precautions for Liquid GasketEBS00REP
REMOVAL OF LIQUID GASKET SEALING

After removing the bolts and nuts, separate the mating surface
and remove the old liquid gasket sealing using Tool.
CAUTION:
Do not damage the mating surfaces.

Tap the seal cutter to insert it.

In areas where the Tool is difficult to use, lightly tap to slide it.
LIQUID GASKET APPLICATION PROCEDURE
1. Remove the old liquid gasket adhering to the gasket applicationsurface and the mating surface using suitable tool.

Remove the liquid gasket completely from the groove of the
liquid gasket application surface, bolts, and bolt holes.
2. Thoroughly clean the mating surfaces and remove adhering moisture, grease and foreign material.
3. Attach the liquid gasket tube to the Tool. Use Genuine RTV Silicone Sealant or equivalent. Refer to
GI-46, "
Recommended Chemical Products and Sealants" .
4. Apply the liquid gasket without breaks to the specified location with the specified dimensions.Tool number : KV10112100 (BT-8653-A)
Tool number : KV10111100 (J-37228)
WBIA0566E
PBIC0003E
Tool number : WS39930000 ( — )
WBIA0567E