2004 INFINITI QX56 check 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

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" .

TERMINOLOGY
GI-51
C
D
E
F
G
H
I
J
K
L
MB
GI
Revision: August 20072004 QX56
Exhaust gas recirculation control-BPT
valveEGRC-BPT valve BPT valve
Exhaust gas recirculation control-solenoid
valveEGRC-solenoid valve EGR control solenoid valve
Exhaust gas recirculation temperature sen-
sor
EGRT sensor Exhaust gas temperature sensor
EGR temperature sensor
Flash electrically erasable programmable
read only memoryFEEPROM ***
Flash erasable programmable read only
memoryFEPROM ***
Flexible fuel sensor FFS ***
Flexible fuel system FF system ***
Fuel pressure regulator *** Pressure regulator
Fuel pressure regulator control solenoid
valve*** PRVR control solenoid valve
Fuel trim FT ***
Heated Oxygen sensor HO2S Exhaust gas sensor
Idle air control system IAC system Idle speed control
Idle air control valve-air regulator IACV-air regulator Air regulator
Idle air control valve-auxiliary air control
valveIACV-AAC valve Auxiliary air control (AAC) valve
Idle air control valve-FICD solenoid valve IACV-FICD solenoid valve FICD solenoid valve
Idle air control valve-idle up control sole-
noid valveIACV-idle up control solenoid valve Idle up control solenoid valve
Idle speed control-FI pot ISC-FI pot FI pot
Idle speed control system ISC system ***
Ignition control IC ***
Ignition control module ICM ***
Indirect fuel injection system IFI system ***
Intake air IA Air
Intake air temperature sensor IAT sensor Air temperature sensor
Knock *** Detonation
Knock sensor KS Detonation sensor
Malfunction indicator lamp MIL Check engine light
Manifold absolute pressure MAP ***
Manifold absolute pressure sensor MAPS ***
Manifold differential pressure MDP ***
Manifold differential pressure sensor MDPS ***
Manifold surface temperature MST ***
Manifold surface temperature sensor MSTS ***
Manifold vacuum zone MVZ ***
Manifold vacuum zone sensor MVZS ***
Mass air flow sensor MAFS Air flow meter
Mixture control solenoid valve MC solenoid valve Air-fuel ratio control solenoid valve
Multiport fuel injection System MFI system Fuel injection controlNEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM

GW-6
SQUEAK AND RATTLE TROUBLE DIAGNOSES
Revision: August 20072004 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 GW-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)

IDX-4
ALPHABETICAL INDEX
Driver air bag .................................................. SRS-45
DTC work support ............................................ EC-113
DTRL - Wiring diagram ....................................... LT-37
Duct and grilles .............................................. ATC-157
DVD Player ........................................................ AV-59
E
ECM input/output signal ..................................... EC-96
ECM power supply ............................. EC-128, EC-361
ECM relay ........................................................ EC-128
ECM/PW - Wiring diagram ............................... EC-362
ECTS - Wiring diagram .................................... EC-167
Electric sunroof .................................................. RF-10
Electric throttle control actuator ......... EC-365, EC-367
Electrical load signal circuit .............................. EC-612
Electrical units location ...................................... PG-64
Electronic ignition (EI) system ........................... EC-28
Engine control circuit diagram ........................... EC-94
Engine control component parts location ........... EC-88
Engine control module (ECM) .......................... EC-351
Engine control system diagram and chart ......... EC-23
Engine coolant .................................................... CO-8
Engine coolant temperature sensor (ECTS) ... EC-165,
EC-178
Engine fail-safe system ...................................... EC-77
Engine oil ............................................................. LU-7
Engine oil filter replacement ............................. MA-16
Engine oil precautions .......................................... GI-7
Engine oil replacement ..................................... MA-16
Engine removal ................................................. EM-70
Engine room cover ............................................ EM-11
Engine serial number .......................................... GI-48
ETC1 - Wiring diagram .................................... EC-368
ETC2 - Wiring diagram .................................... EC-375
ETC3 - Wiring diagram .................................... EC-379
EVAP canister .................................................. EC-636
EVAP canister purge volume control solenoid valve ....
EC-285
, EC-496
EVAP canister vent control valve ....... EC-292, EC-504
EVAP control system (small leak) diagnosis .. EC-276,
EC-316
, EC-324
EVAP control system pressure sensor .... EC-299, EC-
302, EC-308
EVAP control system purge flow monitoring diagnosis
EC-271
EVAP vapor lines inspection ............................. MA-19
Evaporative emission (EVAP) system ............. EC-633
Evaporator ..................................................... ATC-175
Exhaust manifold .............................................. EM-19
Exhaust system ................................................... EX-3
Exhaust system inspection .................................. EX-3
Expansion valve ............................................. ATC-177
F
F/FOG - Wiring diagram ..................................... LT-71
F/PUMP - Wiring diagram ................................ EC-602
Final drive pre-inspection .................. FFD-15, RFD-12
Final drive removal and installation ... FFD-12, RFD-10
Flow charts .......................................................... GI-27
Fluid temperature sensor (A/T) ........................ AT-131
Fluids ................................................................ MA-10
Fluorescent leak detector .............................. ATC-178
Fog lamp, front ................................................... LT-69
Foot lamp ......................................................... LT-129
Freeze frame data ............................... EC-54, EC-107
Front brake solenoid valve ................. AT-151, AT-154
Front bumper ...................................................... EI-13
Front case (Transfer) ....................................... TF-125
Front combination lamp removal and installation LT-33
Front door ............................. BL-129, BL-132, GW-69
Front Door Trim ................................................... EI-31
Front drive shaft (Transfer) .............................. TF-115
Front fog lamp .................................................... LT-69
Front passenger air bag .................................. SRS-50
Front seat ........................................................... SE-96
Front seat belt ...................................................... SB-3
Front seat belt pre-tensioner ............... SRS-3, SRS-57
Front washer ...................................................... WW-4
Front wiper ......................................................... WW-4
FTTS - Wiring diagram ...................... EC-227, EC-232
Fuel cut control (at no load high engine speed) EC-30
Fuel filter replacement ......................................... FL-5
Fuel gauge ............................................................ DI-5
Fuel injection system (Bank 1) .......... EC-208, EC-217
Fuel injection system (Bank 2) .......... EC-208, EC-217
Fuel injector and fuel tube ................................. EM-29
Fuel level sensor ................. EC-334, EC-336, EC-338
Fuel line inspection .............................................. FL-3
Fuel precautions ................................................... GI-5
Fuel pressure check .......................................... EC-46
Fuel pressure release ....................................... EC-46
Fuel pump ....................................................... EC-601
Fuel pump and gauge .......................................... FL-5
Fuel system .......................................................... FL-3
Fuel tank .............................................................. FL-9
Fuel tank temperature sensor ........... EC-225, EC-231
Fuel tank vacuum relief valve ......................... EC-636
FUELB1 - Wiring diagram ................. EC-210, EC-219
FUELB2 - Wiring diagram ................. EC-211, EC-220
Fuse ...................................................... PG-67, PG-77
Fuse and fusible link box .................................. PG-77
Fuse block ......................................................... PG-76
Fusible link ............................................ PG-67, PG-77
G
Garage jack and safety stand ............................. GI-40
Gauges ................................................................. DI-5
Generator .......................................................... SC-17
Generic scan tool (GST) ................................. EC-116
Glass ...................................... GW-11, GW-69, GW-72
Glove box lamp ................................... LT-152, LT-153
GPS antenna ..................................................... AV-62
Grease .............................................................. MA-10
Ground distribution ............................................ PG-30