2004 INFINITI QX56 engine

PRECAUTIONS
GI-5
C
D
E
F
G
H
I
J
K
L
MB
GI
Revision: August 20072004 QX56

Use approved bonding agent, sealants or their equivalents when required.

Use hand tools, power tools (disassembly only) and recom-
mended special tools where specified for safe and efficient ser-
vice repairs.

When repairing the fuel, oil, water, vacuum or exhaust systems,
check all affected lines for leaks.

Before servicing the vehicle:
Protect fenders, upholstery and carpeting with appropriate cov-
ers.
Take caution that keys, buckles or buttons do not scratch paint.
WA RN ING:
To prevent ECM from storing the diagnostic trouble codes, do not carelessly disconnect the harness
connectors which are related to the engine control system and TCM (transmission control module)
system. The connectors should be disconnected only when working according to the WORK FLOW of
TROUBLE DIAGNOSES in EC and AT sections.
Precautions for Three Way CatalystEAS00149
If a large amount of unburned fuel flows into the catalyst, the catalyst temperature will be excessively high. To
prevent this, follow the instructions.

Use unleaded gasoline only. Leaded gasoline will seriously damage the three way catalyst.

When checking for ignition spark or measuring engine compression, make tests quickly and only when
necessary.

Do not run engine when the fuel tank level is low, otherwise the engine may misfire, causing damage to
the catalyst.
Do not place the vehicle on flammable material. Keep flammable material off the exhaust pipe and the three
way catalyst.
Precautions for Fuel (Unleaded Premium Gasoline Required)EAS001KH
Use unleaded premium gasoline with an octane rating of at least 91 AKI (Anti-Knock Index) number (Research
octane number 96).
If unleaded premium gasoline is not available, unleaded regular gasoline with an octane rating of at least 87
AKI number (Research octane number 91) can be used, but only under the following precautions:

have the fuel tank filled only partially with unleaded regular gasoline, and fill up with unleaded premium
gasoline as soon as possible.

avoid full throttle driving and abrupt acceleration.
However, for maximum vehicle performance, the use of unleaded premium gasoline is recommended.
CAUTION:
Do not use leaded gasoline. Using leaded gasoline will damage the three way catalyst. Do not use E-85
fuel (85% fuel ethanol, 15% unleaded gasoline) unless the vehicle is specifically designed for E-85 fuel
PBIC0190E
SGI234

GI-6
PRECAUTIONS
Revision: August 20072004 QX56
(i.e. Flexible Fuel Vehicle - FFV models). Using a fuel other than that specified could adversely affect
the emission control devices and systems, and could also affect the warranty coverage validity.
Precautions for Multiport Fuel Injection System or Engine Control SystemEAS0014B

Before connecting or disconnecting any harness connector for
the multiport fuel injection system or ECM:
Turn ignition switch to “OFF” position.
Disconnect negative battery terminal.
Otherwise, there may be damage to ECM.

Before disconnecting pressurized fuel line from fuel pump to
injectors, be sure to release fuel pressure.

Be careful not to jar components such as ECM and mass air
flow sensor.
Precautions for HosesEAS0014C
HOSE REMOVAL AND INSTALLATION

To prevent damage to rubber hose, do not pry off rubber hose
with tapered tool or screwdriver.

To reinstall the rubber hose securely, make sure of hose inser-
tion length and clamp orientation. (If tube is equipped with hose
stopper, insert rubber hose into tube until it butts up against
hose stopper.)
HOSE CLAMPING

If old rubber hose is re-used, install hose clamp in its original
position (at the indentation where the old clamp was). If there is
a trace of tube bulging left on the old rubber hose, align rubber
hose at that position.

Discard old clamps; replace with new ones.
SGI787
SM A01 9D
SM A02 0D
SM A02 1D

PRECAUTIONS
GI-7
C
D
E
F
G
H
I
J
K
L
MB
GI
Revision: August 20072004 QX56

After installing leaf spring clamps, apply force to them in the
direction of the arrow, tightening rubber hose equally all around.
Precautions for Engine OilsEAS0014D
Prolonged and repeated contact with used engine oil may cause skin cancer. Try to avoid direct skin contact
with used oil.
If skin contact is made, wash thoroughly with soap or hand cleaner as soon as possible.
HEALTH PROTECTION PRECAUTIONS

Avoid prolonged and repeated contact with oils, particularly used engine oils.

Wear protective clothing, including impervious gloves where practicable.

Do not put oily rags in pockets.

Avoid contaminating clothes, particularly underpants, with oil.

Heavily soiled clothing and oil-impregnated footwear should not be worn. Overalls must be cleaned regu-
larly.

First aid treatment should be obtained immediately for open cuts and wounds.

Use barrier creams, applying them before each work period, to help the removal of oil from the skin.

Wash with soap and water to ensure all oil is removed (skin cleansers and nail brushes will help). Prepa-
rations containing lanolin replace the natural skin oils which have been removed.

Do not use gasoline, kerosene, diesel fuel, gas oil, thinners or solvents for cleaning skin.

If skin disorders develop, obtain medical advice without delay.

Where practical, degrease components prior to handling.

Where there is a risk of eye contact, eye protection should be worn, for example, chemical goggles or face
shields; in addition an eye wash facility should be provided.
Precautions for Air ConditioningEAS0014E
Use an approved refrigerant recovery unit any time the air conditioning system must be discharged. Refer to
ATC-162, "
HFC-134a (R-134a) Service Procedure" for specific instructions.
SM A02 2D

HOW TO USE THIS MANUAL
GI-23
C
D
E
F
G
H
I
J
K
L
MB
GI
Revision: August 20072004 QX56D3Drive range 3rd gear
D
4Drive range 4th gear
FR, RR Front, Rear
LH, RH Left-Hand, Right-Hand
M/T Manual Transaxle/Transmission
OD Overdrive
P/S Power Steering
SAE Society of Automotive Engineers, Inc.
SDS Service Data and Specifications
SST Special Service Tools
2WD 2-Wheel Drive
2
22nd range 2nd gear
2
12nd range 1st gear
1
21st range 2nd gear
1
11st range 1st gear ABBREVIATION DESCRIPTION

SERVICE INFORMATION FOR ELECTRICAL INCIDENT
GI-27
C
D
E
F
G
H
I
J
K
L
MB
GI
Revision: August 20072004 QX56
How to Perform Efficient Diagnosis for an Electrical IncidentEAS0014O
WORK FLOW
INCIDENT SIMULATION TESTS
Introduction
Sometimes the symptom is not present when the vehicle is brought in for service. If possible, re-create the
conditions present at the time of the incident. Doing so may help avoid a No Trouble Found Diagnosis. The fol-
lowing section illustrates ways to simulate the conditions/environment under which the owner experiences an
electrical incident.
The section is broken into the six following topics:

Vehicle vibration

Heat sensitive
SG I8 38
STEP DESCRIPTION
STEP 1Get detailed information about the conditions and the environment when the incident occurred.
The following are key pieces of information required to make a good analysis:
WHATVehicle Model, Engine, Transmission/Transaxle and the System (i.e. Radio).
WHENDate, Time of Day, Weather Conditions, Frequency.
WHERERoad Conditions, Altitude and Traffic Situation.
HOWSystem Symptoms, Operating Conditions (Other Components Interaction).
Service History and if any After Market Accessories have been installed.
STEP 2Operate the system, road test if necessary.
Verify the parameter of the incident.
If the problem cannot be duplicated, refer to “Incident Simulation Tests”.
STEP 3Get the proper diagnosis materials together including:

Power Supply Routing

System Operation Descriptions

Applicable Service Manual Sections

Check for any Service Bulletins
Identify where to begin diagnosis based upon your knowledge of the system operation and the customer comments.
STEP 4Inspect the system for mechanical binding, loose connectors or wiring damage.
Determine which circuits and components are involved and diagnose using the Power Supply Routing and Harness
Layouts.
STEP 5 Repair or replace the incident circuit or component.
STEP 6Operate the system in all modes. Verify the system works properly under all conditions. Make sure you have not inad-
vertently created a new incident during your diagnosis or repair steps.

GI-28
SERVICE INFORMATION FOR ELECTRICAL INCIDENT
Revision: August 20072004 QX56

Freezing

Water intrusion

Electrical load

Cold or hot start up
Get a thorough description of the incident from the customer. It is important for simulating the conditions of the
problem.
Vehicle Vibration
The problem may occur or become worse while driving on a rough road or when engine is vibrating (idle with
A/C on). In such a case, you will want to check for a vibration related condition. Refer to the following illustra-
tion.
CONNECTORS & HARNESS
Determine which connectors and wiring harness would affect the electrical system you are inspecting. Gently
shake each connector and harness while monitoring the system for the incident you are trying to duplicate.
This test may indicate a loose or poor electrical connection.
HINT
Connectors can be exposed to moisture. It is possible to get a thin film of corrosion on the connector termi-
nals. A visual inspection may not reveal this without disconnecting the connector. If the problem occurs inter-
mittently, perhaps the problem is caused by corrosion. It is a good idea to disconnect, inspect and clean the
terminals on related connectors in the system.
SENSORS & RELAYS
Gently apply a slight vibration to sensors and relays in the system you are inspecting.
This test may indicate a loose or poorly mounted sensor or relay.
ENGINE COMPARTMENT
There are several reasons a vehicle or engine vibration could cause an electrical complaint. Some of the
things to check for are:

Connectors not fully seated.

Wiring harness not long enough and is being stressed due to engine vibrations or rocking.

Wires laying across brackets or moving components.

Loose, dirty or corroded ground wires.

Wires routed too close to hot components.
To inspect components under the hood, start by verifying the integrity of ground connections. (Refer to Ground
Inspection described later.) First check that the system is properly grounded. Then check for loose connection
by gently shaking the wiring or components as previously explained. Using the wiring diagrams inspect the
wiring for continuity.
BEHIND THE INSTRUMENT PANEL
An improperly routed or improperly clamped harness can become pinched during accessory installation. Vehi-
cle vibration can aggravate a harness which is routed along a bracket or near a screw.
SG I8 39

CONSULT-II CHECKING SYSTEM
GI-37
C
D
E
F
G
H
I
J
K
L
MB
GI
Revision: August 20072004 QX56
CONSULT-II CHECKING SYSTEMPFP:00000
DescriptionEAS001SK

CONSULT-II is a hand-held type tester. When it is connected with a diagnostic connector equipped on the
vehicle side, it will communicate with the control unit equipped in the vehicle and then enable various
kinds of diagnostic tests.

Refer to "CONSULT-II Operator's Manual" for more information.
Function and System ApplicationEAS001SL
x: Applicable.
*1: IVIS (NATS) [INFINITI Vehicle Immobilizer System (Nissan Anti-Theft System)].
*2: This system is shown with IVIS (NATS) using program card AEN04A-1 or later.Diagnostic test
modeFunction
ENGINE
A/T
ALL MODE AWD/4WD
ICC
ABS
AIR BAG
IPDM E/R
BCM
AUTO DRIVE POS.
REARVIEW CAMERA
AIR LEVELIZER
IVIS (NATS)
*1
IVIS (NATS BCM OR S/ENT)
*1
Work supportThis mode enables a technician to adjust some
devices faster and more accurately by following the
indications on CONSULT-II.x - xxx - - xxxx - -
Self-diagnosticSelf-diagnostic can be performed quickly. -----x-------
Self-diagnos-
tic resultsSelf-diagnostic results can be read and erased
quickly.xxxxx - xxx - xxx
Trouble diag-
nostic recordCurrent self-diagnostic results and all trouble diagnos-
tic records previously stored can be read.----- x-------
Data monitor Input/Output data in the ECM can be read. xxxxx - x - xxx - -
Data monitor
(spec)Data monitor specification can be read. x------------
CAN diagno-
sis support
monitorThe communication condition of CAN communication
line can be read.xxxxx - xxx - - - -
Active testDiagnostic Test Mode in which CONSULT-II drives
some actuators apart from the ECMs and also shifts
some parameters in a specified range.x- - xx- x- xxx- -
Function testThis mode can show results of self-diagnosis of ECU
with either “OK” or “NG”. For engines, more practical
tests regarding sensors/switches and/or actuators are
available.xx - - xx - -- - -- -
DTC & SRT
confirmationThe results of SRT (System Readiness Test) and the
self-diagnosis status/result can be confirmed.x------------
DTC work sup-
portThe operating condition to confirm Diagnosis Trouble
Codes can be selected.xx-----------
ECM/ECU part
numberECM/ECU part number can be read. xxxxx - -xx xx - -
ECU discrimi-
nated No.Classification number of a replacement ECU can be
read to prevent an incorrect ECU from being installed.-----x-------
Configuration ECM checks its own NATS communication interface. -------x-----
PIN read
*2This mode shows the BCM-specific 5-digit code. ------------x
Control unit
initialization
*2All registered ignition key IDs in NATS components
can be initialized and new IDs can be registered.-----------x-

CONSULT-II CHECKING SYSTEM
GI-39
C
D
E
F
G
H
I
J
K
L
MB
GI
Revision: August 20072004 QX56
2. If necessary, turn on the ignition switch.
3. Touch “START (NISSAN BASED VHCL)” or System Shortcut
key (eg: ENGINE) on the screen.
CONSULT-II Data Link Connector (DLC) CircuitEAS001SM
INSPECTION PROCEDURE
If the CONSULT-II cannot diagnose the system properly, check the following items:
NOTE:
The preceding schematic is an example and may not be a true representation of the vehicle. The actual DDL1
circuits (CAN lines) from DLC pins 6 and 14 as well as the DDL2 circuit (K-line) from DLC pin 7 may be con-
nected to more than one system. A short in a DDL circuit connected to a control unit in one system may affect
CONSULT-II access to other systems.
BCIA0029E
LAIA0028E
Symptom Check item
CONSULT-II cannot access
any system.

CONSULT-II DLC power supply circuit (Terminal 8) and ground circuit (Terminal 4). For detailed cir-
cuit, refer to LAN-5, "
CAN Communication Unit" .

CONSULT-II DLC cable and CONSULT-II CONVERTER.
CONSULT-II cannot access
individual system. (Other sys-
tems can be accessed.)

CONSULT-II program card (Check the appropriate CONSULT-II program card for the system.
Refer to GI-38, "
Checking Equipment" .

Power supply and ground circuit for the control unit of the system (For detailed circuit, refer to wir-
ing diagram for each system.)

Open or short circuit between the system and CONSULT-II DLC (For detailed circuit, refer to wiring
diagram for each system.)

Open or short circuit in CAN or K communication line. Refer to LAN-3, "Precautions When Using
CONSULT-II" .