2004 INFINITI QX56 Engine Control System

MA-4
GENERAL MAINTENANCE
Revision: August 20072004 QX56
GENERAL MAINTENANCEPFP:00000
General MaintenanceELS000ZZ
General maintenance includes those items which should be checked during the normal day-to-day operation
of the vehicle. They are essential if the vehicle is to continue operating properly. The owner can perform these
checks and inspections or have their NISSAN dealers perform them.
OUTSIDE THE VEHICLE
The maintenance items listed here should be performed from time to time, unless otherwise specified.
INSIDE THE VEHICLE
The maintenance items listed here should be checked on a regular basis, such as when performing periodic maintenance, cleaning the
vehicle, etc.ItemReference page
TiresCheck the pressure with a gauge at least once a month and always prior to a
long distance trip. Adjust to the specified pressure if necessary. Check carefully
for damage, cuts or excessive wear.—
Wheel lug nutsWhen checking the tires, make sure no nuts are missing, and check for any
loose nuts. Tighten if necessary.WT-6, "
Rotation"
WindshieldClean the windshield on a regular basis. Check the windshield at least every six
months for cracks or other damage. Repair as necessary.
Tire rotationTires should be rotated every 12,000 km (7,500 miles).WT-6, "
Rotation"
Wheel alignment and
balanceIf the vehicle pulls to either side while driving on a straight and level road, or if
you detect uneven or abnormal tire wear, there may be a need for wheel align-
ment. If the steering wheel or seat vibrates at normal highway speeds, wheel
balancing may be needed.WT-5, "Balancing
Wheels", FSU-6, "Front
Wheel Alignment"
Windshield wiper
bladesCheck for cracks or wear if they do not wipe properly.
—
Doors and engine
hoodCheck that all doors and the engine hood operate smoothly as well as the back
hatch. Also make sure that all latches lock securely. Lubricate if necessary.
Make sure that the secondary latch keeps the hood from opening when the pri-
mary latch is released.
When driving in areas using road salt or other corrosive materials, check lubri-
cation frequently.MA-30, "
Lubricating
Locks, Hinges and Hood
Latches"
Lamps
Make sure that the head lamps, stop lamps, tail lamps, turn signal lamps, and
other lamps are all operating properly and installed securely. Also check head
lamp aim. Clean the head lamps on a regular basis.LT- 3 1 , "Aiming Adjust-
ment" for US, LT- 4 6 ,
"Aiming Adjustment" f o r
Canada
ItemReference page
Warning lamps and
buzzers/chimesMake sure that all warning lamps and buzzers/chimes are operating properly.DI-25, "
Electrical Com-
ponents Inspection"
Windshield wiper and
washerCheck that the wipers and washer operate properly and that the wipers do not
streak.—
Windshield defrosterCheck that the air comes out of the defroster outlets properly and in sufficient
quantity when operating the heater or air conditioner.—
Steering wheelCheck that it has the specified play. Be sure to check for changes in the steering
condition, such as excessive play, hard steering or strange noises.PS-7, "
CHECKING
STEERING WHEEL
PLAY"
SeatsCheck seat position controls such as seat adjusters, seat back recliner, etc. to
make sure they operate smoothly and that all latches lock securely in every
position. Check that the head restraints move up and down smoothly and that
the locks (if equipped) hold securely in all latched positions. Check that the
latches lock securely for folding-down rear seat backs.—
Seat beltsCheck that all parts of the seat belt system (e.g. buckles, anchors, adjusters and
retractors) operate properly and smoothly and are installed securely. Check the
belt webbing for cuts, fraying, wear or damage.SB-10, "
Seat Belt
Inspection", MA-31,
"Checking Seat Belts,
Buckles, Retractors,
Anchors and Adjusters"
Accelerator pedalCheck the pedal for smooth operation. Keep the floor mats away from the pedal. —

GENERAL MAINTENANCE
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UNDER THE HOOD AND VEHICLE
The maintenance items listed here should be checked periodically (e.g. each time you check the engine oil or refuel).BrakesCheck that the brake does not pull the vehicle to one side when applied. —
Brake pedal and
boosterCheck the pedal for smooth operation and make sure it has the proper distance
under it when depressed fully. Check the brake booster function. Keep the floor
mats away from the pedal.BR-6, "
Inspection and
Adjustment", BR-17,
"On-Vehicle Service"
Parking brakeCheck that the parking brake control has the proper travel and make sure that
the vehicle is held securely on a fairly steep hill when only the parking brake is
applied.PB-3, "On-Vehicle Ser-
vice"
Automatic transmis-
sion “Park” mecha-
nismOn a fairly steep hill check that the vehicle is held securely with the selector
lever in the P position without applying the brakes. — ItemReference page
ItemReference page
Windshield washer
fluidCheck that there is adequate fluid in the tank.
—
Engine coolant levelCheck the coolant level when the engine is cold.MA-12
Radiator and hosesCheck the front of the radiator and clean off any dirt, insects, leaves, etc., that
may have accumulated. Make sure the hoses have no cracks, deformation,
deterioration or loose connections.—
Brake fluid levelMake sure that the brake fluid level is between the “MAX” and “MIN” lines on the
reservoirsMA-27
BatteryCheck the fluid level in each cell. It should be between the “MAX” and “MIN”
lines. Vehicles operated in high temperatures or under severe conditions require
frequent checks of the battery fluid level.—
Engine drive beltMake sure that no belt is frayed, worn, cracked or oily.MA-12
Engine oil levelCheck the level on the dipstick after parking the vehicle on a level spot and turn-
ing off the engine.MA-16
Power steering fluid
level and linesCheck the level on the reservoir with the engine off. Check the lines for improper
attachment, leaks, cracks, etc.MA-29
Automatic transmis-
sion fluid levelCheck the level on the dipstick after putting the selector lever in “P” with the
engine idling.MA-21
Exhaust systemMake sure there are no loose supports, cracks or holes. If the sound of the
exhaust seems unusual or there is a smell of exhaust fumes, immediately locate
the trouble and correct it.MA-21
UnderbodyThe underbody is frequently exposed to corrosive substances such as those
used on icy roads or to control dust. It is very important to remove these sub-
stances, otherwise rust will form on the floor pan, frame, fuel lines and around
the exhaust system. At the end of winter, the underbody should be thoroughly
flushed with plain water, being careful to clean those areas where mud and dirt
can easily accumulate.—
Fluid leaksCheck under the vehicle for fuel, oil, water or other fluid leaks after the vehicle
has been parked for a while. Water dripping from the air conditioner after use is
normal. If you should notice any leaks or gasoline fumes are evident, check for
the cause and correct it immediately.—

MA-6
PERIODIC MAINTENANCE
Revision: August 20072004 QX56
PERIODIC MAINTENANCEPFP:00026
Introduction of Periodic MaintenanceELS00100
Two different maintenance schedules are provided, and should be used, depending upon the conditions in
which the vehicle is mainly operated. After 60,000 miles (96,000 km) or 48 months, continue the periodic
maintenance at the same mileage or time intervals, whichever comes first.
Maintenance For Off-road Driving (4WD only)ELS0012H
After driving the vehicle off-road through sand, mud, or water; more frequent maintenance may be required for
the following items:
Brake pads and rotors
Brake lines and hoses
Rear final drive oil, transmission fluid, and transfer fluid
Steering linkage
Drive shafts
Engine air cleaner filter
In-cabin microfilters
Schedule 1ELS00101
EMISSION CONTROL SYSTEM MAINTENANCE
Abbreviations: R = Replace. I = Inspect. Correct or replace if necessary. [ ]: At the mileage intervals only Schedule 1Follow Periodic Maintenance Schedule 1 if your driving habits frequently includes
one or more of the following driving conditions:

Repeated short trips of less than 5 miles (8 km).

Repeated short trips of less than 10 miles (16 km) with outside temperatures
remaining below freezing.

Operating in hot weather in stop-and-go “rush hour” traffic.

Extensive idling and/or low speed driving for long distances, such as police,
taxi or door-to-door delivery use.

Driving in dusty conditions.

Driving on rough, muddy, or salt spread roads.

Towing a trailer or using a car-top carrier.Emission Control Sys-
tem MaintenanceMA-6
Chassis and Body
MaintenanceMA-6
Schedule 2Follow Periodic Maintenance Schedule 2 if none of the driving conditions shown
in Schedule 1 apply to the driving habits.Emission Control Sys-
tem MaintenanceMA-8Chassis and Body
MaintenanceMA-8
MAINTENANCE OPERATIONMAINTENANCE INTERVAL
Reference
Section -
Page or -
Content Title Perform at number of miles,
kilometers or months, which-
ever comes first.Miles x 1,000
(km x 1,000)
Months3.75
(6)
37.50
(12)
611 . 2 5
(18)
915
(24)
1218.75
(30)
1522.5
(36)
1826.25
(42)
2130
(48)
24
Drive belts NOTE (1)MA-12
Air cleaner filter NOTE (2) [R]MA-15
EVAP vapor linesI*MA-19
Fuel linesI*MA-15
Fuel filter NOTE (3)—
Engine coolant NOTE (4)MA-12
Engine oil R R RRRRRRMA-16
Engine oil filter R R RRRRRRMA-16
Spark plugs (double PLATI-
NUM-TIPPED type)Replace every 105,000 miles (169,000 km).MA-17
Intake and exhaust valve
clearance*NOTE (5)EM-52

MA-8
PERIODIC MAINTENANCE
Revision: August 20072004 QX56
(1) If towing a trailer, or using a car-top carrier, or driving on rough or muddy roads, change (not just inspect) oil at every 30,000 miles
(48,000 km) or 24 months.
(2) Refer to “Tire rotation” under the “General maintenance” heading earlier in this section.
Schedule 2ELS00102
EMISSION CONTROL SYSTEM MAINTENANCE
Abbreviations: R = Replace. I = Inspect. Correct or replace if necessary. [ ]: At the mileage intervals only
(1) After 60,000 miles (96,000 km) or 48 months, inspect every 15,000 miles (24,000 km) or 12 months. Replace drive belts if damaged.
(2) Maintenance-free item. For service procedures, go to FL section.
(3) After 60,000 miles (96,000 km) or 48 months, replace every 30,000 miles (48,000 km) or 24 months.
(4) If valve noise increases, inspect valve clearance.
* Maintenance items and intervals with “*” are recommended by NISSAN for reliable vehicle operation. The owner need not perform
such maintenance in order to maintain the emission warranty or manufacturer recall liability. Other maintenance items and intervals are
required. MAINTENANCE OPERATIONMAINTENANCE INTERVAL
Reference
Section
- Page
or
- Content
Title Perform at number of miles, kilometers or
months, whichever comes first.Miles x
1,000
(km x
1,000)
Months33.75
(54)
2737.5
(60)
3041.25
(66)
3345
(72)
3648.75
(78)
3952.5
(84)
4256.25
(90)
4560
(96)
48
Brake lines and cables I IMA-27
Brake pads and rotors I I I IMA-28
Automatic transmission fluid NOTE (1) I IMA-21
Transfer fluid and front final drive oil NOTE (1) I IMA-24,
MA-24
Rear final drive oil NOTE (1) I IMA-24,
MA-24
Steering gear, linkage, axle, and suspension
partsII IIMA-28,
MA-29
Tire Rotation NOTE (2)MA-27
Drive shaft boots and propeller shaft (4WD) I I I IMA-24
Exhaust system I I I IMA-21
In-cabin microfilter R RAT C - 1 4 2
MAINTENANCE OPERATIONMAINTENANCE INTERVAL
Reference
Section - Page
or - Content
Title Perform at number of miles,
kilometers or months, whichever
comes first.Miles x 1,000
(km x 1,000)
Months7.5
(12)
615
(24)
1222.5
(36)
1830
(48)
2437.5
(60)
3045
(72)
3652.5
(84)
4260
(96)
48
Drive belts NOTE (1) I*MA-12
Air cleaner filter [R] [R]MA-15
EVAP vapor lines I* I*MA-19
Fuel lines I* I*MA-15
Fuel filter NOTE (2)—
Engine coolant NOTE (3) R*MA-12
Engine oil R R R R R R R RMA-16
Engine oil filter R R R R R R R RMA-16
Spark plugs (PLATINUM-
TIPPED type)Replace every 105,000 miles (169,000 km).MA-17
Intake and exhaust valve clear-
ance*NOTE (4)EM-52

ENGINE MAINTENANCE
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3. Open the radiator drain plug at the bottom of the radiator, and
remove the radiator filler cap. This is the only step required
when partially draining the cooling system (radiator only).
CAUTION:
Do not to allow the coolant to contact the drive belts.
4. When draining all of the coolant in the system for engine
removal or repair, it is necessary to drain the cylinder block.
Remove the RH cylinder block drain plug to drain the right bank
and the oil cooler hose to drain the left bank as shown.
5. Remove the reservoir tank to drain the engine coolant, then clean the reservoir tank before installing it.
6. Check the drained coolant for contaminants such as rust, corrosion or discoloration.
If the coolant is contaminated, flush the engine cooling system. Refer to MA-14, "
FLUSHING COOLING
SYSTEM" .
REFILLING ENGINE COOLANT
1. Close the radiator drain plug. Install the reservoir tank, cylinder block drain plug, and the oil cooler hose, if
removed for a total system drain or for engine removal or repair.

The radiator must be completely empty of coolant and water.

Apply sealant to the threads of the cylinder block drain plug. Use Genuine High Performance Thread
Sealant or equivalent. Refer to GI-45, "
RECOMMENDED CHEMICAL PRODUCTS AND SEALANTS" .
2. Set the vehicle heater controls to the full HOT and heater ON position. Turn the vehicle ignition ON with
the engine OFF as necessary to activate the heater mode.
3. Remove the vented reservoir cap and replace it with a non-vented reservoir cap before filling the cooling
system.
WBIA0391E
PBIC0146E
WBIA0392E
Radiator drain plug : Refer to CO-10, "RADIATOR" .
RH cylinder block drain plug : Refer to EM-73, "
CYLINDER BLOCK" .

PG-1
POWER SUPPLY, GROUND & CIRCUIT ELEMENTS
K ELECTRICAL
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Revision: August 20072004 QX56 PRECAUTIONS .......................................................... 3
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 3
Wiring Diagrams and Trouble Diagnosis .................. 3
POWER SUPPLY ROUTING CIRCUIT ...................... 4
Schematic ................................................................ 4
Wiring Diagram — POWER — ................................. 6
BATTERY POWER SUPPLY — IGNITION SW.
IN ANY POSITION ................................................ 6
ACCESSORY POWER SUPPLY — IGNITION
SW. IN ACC OR ON .............................................11
IGNITION POWER SUPPLY — IGNITION SW.
IN ON .................................................................. 12
IGNITION POWER SUPPLY — IGNITION SW.
IN ON AND/OR START ....................................... 13
IPDM E/R (INTELLIGENT POWER DISTRIBUTION
MODULE ENGINE ROOM) ...................................... 17
System Description ................................................ 17
SYSTEMS CONTROLLED BY IPDM E/R ........... 17
CAN COMMUNICATION LINE CONTROL ......... 17
IPDM E/R STATUS CONTROL ........................... 18
CAN Communication System Description .............. 18
Function of Detecting Ignition Relay Malfunction ... 18
CONSULT-II Function (IPDM E/R) ......................... 19
CONSULT-II BASIC OPERATION ...................... 19
SELF-DIAGNOSTIC RESULTS .......................... 20
DATA MONITOR ................................................. 20
ACTIVE TEST ..................................................... 22
Auto Active Test ..................................................... 23
DESCRIPTION .................................................... 23
OPERATION PROCEDURE ............................... 23
INSPECTION IN AUTO ACTIVE TEST MODE ... 23
Schematic .............................................................. 25
IPDM E/R Terminal Arrangement ........................... 26
IPDM E/R Power/Ground Circuit Inspection .......... 27
Inspection with CONSULT-II (Self-Diagnosis) ........ 28
Removal and Installation of IPDM E/R ................... 29
REMOVAL ........................................................... 29
INSTALLATION ................................................... 29GROUND CIRCUIT ................................................... 30
Ground Distribution ................................................. 30
MAIN HARNESS ................................................. 30
ENGINE ROOM HARNESS ................................ 33
ENGINE CONTROL HARNESS .......................... 36
BODY HARNESS ................................................ 37
BODY NO. 2 HARNESS ..................................... 38
BACK DOOR NO. 2 RH HARNESS .................... 39
HARNESS ................................................................. 40
Harness Layout ...................................................... 40
HOW TO READ HARNESS LAYOUT ................. 40
OUTLINE ............................................................. 41
MAIN HARNESS ................................................. 42
ENGINE ROOM HARNESS (LH VIEW) .............. 44
ENGINE ROOM HARNESS (RH VIEW) ............. 47
ENGINE CONTROL HARNESS .......................... 49
CHASSIS HARNESS .......................................... 51
BODY HARNESS ................................................ 53
BODY NO. 2 HARNESS ..................................... 55
ROOM LAMP HARNESS .................................... 57
FRONT DOOR LH HARNESS ............................ 58
FRONT DOOR RH HARNESS ............................ 58
REAR DOOR LH HARNESS ............................... 59
REAR DOOR RH HARNESS .............................. 59
BACK DOOR HARNESS .................................... 60
Wiring Diagram Codes (Cell Codes) ...................... 61
ELECTRICAL UNITS LOCATION ............................ 64
Electrical Units Location ......................................... 64
ENGINE COMPARTMENT .................................. 64
PASSENGER COMPARTMENT ......................... 65
Fuse ........................................................................ 67
Fusible Link ............................................................ 67
Circuit Breaker (Built Into BCM) ............................. 67
HARNESS CONNECTOR ......................................... 68
Description .............................................................. 68
HARNESS CONNECTOR (TAB-LOCKING
TYPE) .................................................................. 68
HARNESS CONNECTOR (SLIDE-LOCKING
TYPE) .................................................................. 69
HARNESS CONNECTOR (DIRECT-CONNECT

IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE ROOM)
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IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE ROOM)
PFP:284B7
System DescriptionEKS007NN

IPDM E/R (Intelligent Power Distribution Module Engine Room) integrates the relay box and fuse block
which were originally placed in engine compartment. It controls integrated relays via IPDM E/R control cir-
cuits.

IPDM E/R-integrated control circuits perform ON-OFF operation of relays, CAN communication control,
etc.

It controls operation of each electrical component via ECM, BCM and CAN communication lines.
CAUTION:
None of the IPDM E/R integrated relays can be removed.
SYSTEMS CONTROLLED BY IPDM E/R
1. Lamp control
Using CAN communication lines, it receives signals from the BCM and controls the following lamps:

Headlamps (Hi, Lo)

Parking lamps

Tail lamps

Front fog lamps
2. Wiper control
Using CAN communication lines, it receives signals from the BCM and controls the front wipers.
3. Rear window defogger relay control
Using CAN communication lines, it receives signals from the BCM and controls the rear window defogger
relay.
4. A/C compressor control
Using CAN communication lines, it receives signals from the ECM and controls the A/C compressor
(magnetic clutch).
5. Starter control
Using CAN communication lines, it receives signals from the ECM and controls the starter relay.
6. Cooling fan control
Using CAN communication lines, it receives signals from the ECM and controls the cooling fan relays.
7. Horn control
Using CAN communication lines, it receives signals from the BCM and controls the horn relay.
CAN COMMUNICATION LINE CONTROL
With CAN communication, by connecting each control unit using two communication lines (CAN L-line, CAN
H-line), it is possible to transmit a maximum amount of information with minimum wiring. Each control unit can
transmit and receive data, and reads necessary information only.
1. Fail-safe control

When CAN communication with other control units is impossible, IPDM E/R performs fail-safe control.
After CAN communication returns to normal operation, it also returns to normal control.

Operation of control parts by IPDM E/R during fail-safe mode is as follows:
Controlled system Fail-safe mode
Headlamp

With the ignition switch ON, the headlamp (low) is ON.

With the ignition switch OFF, the headlamp (low) is OFF.
Tail and parking lamps

With the ignition switch ON, the tail and parking lamps are ON.

With the ignition switch OFF, the tail and parking lamps are OFF.
Cooling fan

With the ignition switch ON, the cooling fan HI operates.

With the ignition switch OFF, the cooling fan stops.
Front wiperUntil the ignition switch is turned off, the front wiper LO and HI remains in the same status it
was in just before fail−safe control was initiated.
Rear window defogger Rear window defogger relay OFF

PG-18
IPDM E/R (INTELLIGENT POWER DISTRIBUTION MODULE ENGINE ROOM)
Revision: August 20072004 QX56
IPDM E/R STATUS CONTROL
In order to save power, IPDM E/R switches status automatically based on each operating condition.
1. CAN communication status

CAN communication is normally performed with other control units.

Individual unit control by IPDM E/R is normally performed.

When sleep request signal is received from BCM, mode is switched to sleep waiting status.
2. Sleep waiting status

Process to stop CAN communication is activated.

All systems controlled by IPDM E/R are stopped. When 1 second has elapsed after CAN communica-
tion with other control units is stopped, mode switches to sleep status.
3. Sleep status

IPDM E/R operates in low current-consumption mode.

CAN communication is stopped.

When a change in CAN communication signal is detected, mode switches to CAN communication sta-
tus.

When a change in ignition switch signal is detected, mode switches to CAN communication status.
CAN Communication System DescriptionEKS007NO
Refer to LAN-5, "CAN COMMUNICATION" .
Function of Detecting Ignition Relay MalfunctionEKS007NP

When the integrated ignition relay is stuck in a "closed contact" position and cannot be turned OFF, IPDM
E/R turns ON tail and parking lamps for 10 minutes to indicate IPDM E/R malfunction.

When the state of the integrated ignition relay does not agree with the state of the ignition switch signal
received via CAN communication, the IPDM E/R activates the tail lamp relay.
NOTE:
When the ignition switch is turned ON, the tail lamps are OFF.
A/C compressor A/C compressor OFF
Front fog lamps Front fog lamp relay OFFControlled system Fail-safe mode
Ignition switch signal Ignition relay status Tail lamp relay
ON ON —
OFF OFF —
ON OFF —
OFF ON ON (10 minutes)