2004 INFINITI QX56 engine

REAR VIEW MONITOR
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Revision: August 20072004 QX56
Side Distance Guideline CorrectionEKS007RA
This mode is used to modify the side distance guidelines if they are dislocated from the rear view monitor
image, because of variations of body/camera mounting conditions.
SIDE DISTANCE GUIDELINE CORRECTION PROCEDURE
1. Create a correction line to modify the screen.
Draw lines on the rearward of the vehicle passing through the
following points: 200 mm (7.87 inch) from both sides of the vehi-
cle, and

*1: 0.5 m (1.5 feet)

*2: 1 m (3 feet)

*3: 2 m (7 feet)

*4: 3 m (10 feet)
and from the rear end of the bumper
2. With the ignition switch OFF, connect “CONSULT-II” and “CON-
SULT-II CONVERTER” to the data link connector, then turn igni-
tion switch ON. Touch “REARVIEW CAMERA” on “SELECT
SYSTEM” screen.
CAUTION:
Stop engine for safety when correcting side distance guide-
line.
3. Shift the A/T select lever to R position.
4. Touch “SELCT GUIDELINE PATTERN” on “SELECT WORK
ITEM” screen.
SKIA5637E
SKIA6103E
SKIA5638E

EC-1
ENGINE CONTROL SYSTEM
B ENGINE
CONTENTS
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SECTION EC
A
EC
Revision: August 20072004 QX56 INDEX FOR DTC ........................................................ 8
Alphabetical Index .................................................... 8
DTC No. Index ....................................................... 12
PRECAUTIONS ........................................................ 16
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” ................................................................ 16
On Board Diagnostic (OBD) System of Engine and
A/T .......................................................................... 16
Precaution .............................................................. 16
Wiring Diagrams and Trouble Diagnosis ................ 19
PREPARATION ......................................................... 20
Special Service Tools ............................................. 20
Commercial Service Tools ...................................... 22
ENGINE CONTROL SYSTEM .................................. 23
System Diagram ..................................................... 23
Vacuum Hose Drawing ........................................... 24
System Chart ......................................................... 25
Multiport Fuel Injection (MFI) System .................... 26
Electronic Ignition (EI) System ............................... 28
Nissan Torque Demand (NTD) Control System ..... 29
Air Conditioning Cut Control ................................... 30
Fuel Cut Control (at No Load and High Engine
Speed) .................................................................... 30
CAN communication .............................................. 31
BASIC SERVICE PROCEDURE .............................. 32
Idle Speed and Ignition Timing Check .................... 32
Idle Speed/Ignition Timing/Idle Mixture Ratio
Adjustment ............................................................. 33
Accelerator Pedal Released Position Learning ...... 44
Throttle Valve Closed Position Learning ................ 44
Idle Air Volume Learning ........................................ 44
Fuel Pressure Check .............................................. 46
ON BOARD DIAGNOSTIC (OBD) SYSTEM ............ 49
Introduction ............................................................ 49
Two Trip Detection Logic ........................................ 49
Emission-related Diagnostic Information ................ 50
IVIS (Infiniti Vehicle Immobilizer System — NATS) ... 63
Malfunction Indicator Lamp (MIL) ........................... 63
OBD System Operation Chart ................................ 66TROUBLE DIAGNOSIS ............................................ 71
Trouble Diagnosis Introduction ............................... 71
DTC Inspection Priority Chart ................................. 76
Fail-safe Chart ........................................................ 77
Basic Inspection ..................................................... 79
Symptom Matrix Chart ............................................ 84
Engine Control Component Parts Location ............ 88
Circuit Diagram ....................................................... 94
ECM Harness Connector Terminal Layout ............. 96
ECM Terminals and Reference Value ..................... 96
CONSULT-II Function ...........................................103
Generic Scan Tool (GST) Function .......................116
CONSULT-II Reference Value in Data Monitor .....118
Major Sensor Reference Graph in Data Monitor
Mode .....................................................................121
TROUBLE DIAGNOSIS - SPECIFICATION VALUE .123
Description ............................................................123
Testing Condition ..................................................123
Inspection Procedure ............................................123
Diagnostic Procedure ...........................................124
TROUBLE DIAGNOSIS FOR INTERMITTENT INCI-
DENT .......................................................................127
Description ............................................................127
Diagnostic Procedure ...........................................127
POWER SUPPLY AND GROUND CIRCUIT ...........128
Wiring Diagram .....................................................128
Diagnostic Procedure ...........................................129
Ground Inspection ................................................133
DTC U1000, U1001 CAN COMMUNICATION LINE .135
Description ............................................................135
On Board Diagnosis Logic ....................................135
DTC Confirmation Procedure ...............................135
Wiring Diagram .....................................................136
Diagnostic Procedure ...........................................137
DTC P0037, P0038, P0057, P0058 HO2S2 HEATER .138
Description ............................................................138
CONSULT-II Reference Value in Data Monitor Mode
.138
On Board Diagnosis Logic ....................................138
DTC Confirmation Procedure ...............................139

EC-5
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ECA
Revision: August 20072004 QX56 Overall Function Check ........................................ 396
Wiring Diagram .................................................... 398
Diagnostic Procedure ........................................... 401
Component Inspection ......................................... 404
Removal and Installation ...................................... 406
DTC P1148, P1168 CLOSED LOOP CONTROL .... 407
On Board Diagnosis Logic ................................... 407
DTC P1211 TCS CONTROL UNIT ......................... 408
Description ........................................................... 408
On Board Diagnosis Logic ................................... 408
DTC Confirmation Procedure ............................... 408
Diagnostic Procedure ........................................... 408
DTC P1212 TCS COMMUNICATION LINE ............ 409
Description ........................................................... 409
On Board Diagnosis Logic ................................... 409
DTC Confirmation Procedure ............................... 409
Diagnostic Procedure ........................................... 409
DTC P1217 ENGINE OVER TEMPERATURE ....... 410
Description ........................................................... 410
CONSULT-II Reference Value in Data Monitor Mode
. 410
On Board Diagnosis Logic .................................... 411
Overall Function Check ......................................... 411
Wiring Diagram .................................................... 413
Diagnostic Procedure ........................................... 415
Main 12 Causes of Overheating ........................... 418
Component Inspection ......................................... 419
DTC P1225 TP SENSOR ........................................ 420
Component Description ........................................ 420
On Board Diagnosis Logic ................................... 420
DTC Confirmation Procedure ............................... 420
Diagnostic Procedure ........................................... 421
Removal and Installation ...................................... 421
DTC P1226 TP SENSOR ........................................ 422
Component Description ........................................ 422
On Board Diagnosis Logic ................................... 422
DTC Confirmation Procedure ............................... 422
Diagnostic Procedure ........................................... 423
Removal and Installation ...................................... 423
DTC P1229 SENSOR POWER SUPPLY ................ 424
On Board Diagnosis Logic ................................... 424
DTC Confirmation Procedure ............................... 424
Wiring Diagram .................................................... 425
Diagnostic Procedure ........................................... 426
DTC P1271, P1281 A/F SENSOR 1 ....................... 429
Component Description ........................................ 429
CONSULT-II Reference Value in Data Monitor Mode
. 429
On Board Diagnosis Logic ................................... 429
DTC Confirmation Procedure ............................... 429
Wiring Diagram .................................................... 431
Diagnostic Procedure ........................................... 434
Removal and Installation ...................................... 436
DTC P1272, P1282 A/F SENSOR 1 ....................... 437
Component Description ........................................ 437
CONSULT-II Reference Value in Data Monitor Mode
. 437
On Board Diagnosis Logic ................................... 437
DTC Confirmation Procedure ............................... 437Wiring Diagram .....................................................439
Diagnostic Procedure ...........................................442
Removal and Installation ......................................444
DTC P1273, P1283 A/F SENSOR 1 .......................445
Component Description ........................................445
CONSULT-II Reference Value in Data Monitor Mode
.445
On Board Diagnosis Logic ....................................445
DTC Confirmation Procedure ...............................445
Wiring Diagram .....................................................447
Diagnostic Procedure ...........................................450
Removal and Installation ......................................453
DTC P1274, P1284 A/F SENSOR 1 .......................454
Component Description ........................................454
CONSULT-II Reference Value in Data Monitor Mode
.454
On Board Diagnosis Logic ....................................454
DTC Confirmation Procedure ...............................454
Wiring Diagram .....................................................456
Diagnostic Procedure ...........................................459
Removal and Installation ......................................462
DTC P1276, P1286 A/F SENSOR 1 .......................463
Component Description ........................................463
CONSULT-II Reference Value in Data Monitor Mode
.463
On Board Diagnosis Logic ....................................463
DTC Confirmation Procedure ...............................463
Overall Function Check ........................................464
Wiring Diagram .....................................................466
Diagnostic Procedure ...........................................469
Removal and Installation ......................................471
DTC P1278, P1288 A/F SENSOR 1 .......................472
Component Description ........................................472
CONSULT-II Reference Value in Data Monitor Mode
.472
On Board Diagnosis Logic ....................................472
DTC Confirmation Procedure ...............................473
Wiring Diagram .....................................................475
Diagnostic Procedure ...........................................478
Removal and Installation ......................................483
DTC P1279, P1289 A/F SENSOR 1 .......................484
Component Description ........................................484
CONSULT-II Reference Value in Data Monitor Mode
.484
On Board Diagnosis Logic ....................................484
DTC Confirmation Procedure ...............................485
Wiring Diagram .....................................................487
Diagnostic Procedure ...........................................490
Removal and Installation ......................................495
DTC P1444 EVAP CANISTER PURGE VOLUME
CONTROL SOLENOID VALVE ...............................496
Description ............................................................496
CONSULT-II Reference Value in Data Monitor Mode
.496
On Board Diagnosis Logic ....................................497
DTC Confirmation Procedure ...............................497
Wiring Diagram .....................................................498
Diagnostic Procedure ...........................................500

EC-7
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ECA
Revision: August 20072004 QX56 Component Inspection ......................................... 582
Removal and Installation ...................................... 582
IGNITION SIGNAL .................................................. 583
Component Description ........................................ 583
Wiring Diagram .................................................... 584
Diagnostic Procedure ........................................... 589
Component Inspection ......................................... 593
Removal and Installation ...................................... 594
INJECTOR CIRCUIT ............................................... 595
Component Description ........................................ 595
CONSULT-II Reference Value in Data Monitor Mode
. 595
Wiring Diagram .................................................... 596
Diagnostic Procedure ........................................... 597
Component Inspection ......................................... 600
Removal and Installation ...................................... 600
FUEL PUMP CIRCUIT ............................................ 601
Description ........................................................... 601
CONSULT-II Reference Value in Data Monitor Mode
. 601
Wiring Diagram .................................................... 602
Diagnostic Procedure ........................................... 603
Component Inspection ......................................... 606
Removal and Installation ...................................... 606
REFRIGERANT PRESSURE SENSOR ................. 607
Component Description ........................................ 607
Wiring Diagram .................................................... 608
Diagnostic Procedure ........................................... 609
Removal and Installation ....................................... 611
ELECTRICAL LOAD SIGNAL ................................ 612
Description ........................................................... 612
CONSULT-II Reference Value in Data Monitor Mode
. 612
Diagnostic Procedure ........................................... 612
ICC BRAKE SWITCH ............................................. 613
Component Description ........................................ 613
CONSULT-II Reference Value in Data Monitor Mode
. 613
Wiring Diagram .................................................... 614
Diagnostic Procedure ........................................... 615
Component Inspection ......................................... 619
ASCD BRAKE SWITCH ......................................... 621
Component Description ........................................ 621CONSULT-II Reference Value in Data Monitor Mode
.621
Wiring Diagram .....................................................622
Diagnostic Procedure ...........................................623
Component Inspection ..........................................627
ASCD INDICATOR ..................................................628
Component Description ........................................628
CONSULT-II Reference Value in Data Monitor Mode
.628
Wiring Diagram .....................................................629
Diagnostic Procedure ...........................................630
MIL AND DATA LINK CONNECTOR ......................631
Wiring Diagram .....................................................631
EVAPORATIVE EMISSION SYSTEM .....................633
Description ............................................................633
Component Inspection ..........................................636
Removal and Installation ......................................637
How to Detect Fuel Vapor Leakage ......................637
ON BOARD REFUELING VAPOR RECOVERY
(ORVR) ....................................................................640
System Description ...............................................640
Diagnostic Procedure ...........................................641
Component Inspection ..........................................643
POSITIVE CRANKCASE VENTILATION ...............645
Description ............................................................645
Component Inspection ..........................................645
AUTOMATIC SPEED CONTROL DEVICE (ASCD) .647
System Description ...............................................647
Component Description ........................................648
SERVICE DATA AND SPECIFICATIONS (SDS) ....649
Fuel Pressure .......................................................649
Idle Speed and Ignition Timing .............................649
Calculated Load Value ..........................................649
Mass Air Flow Sensor ...........................................649
Intake Air Temperature Sensor .............................649
Engine Coolant Temperature Sensor ...................649
A/F Sensor 1 Heater .............................................649
Heated Oxygen sensor 2 Heater ..........................649
Crankshaft Position Sensor (POS) .......................649
Camshaft Position Sensor (PHASE) ....................649
Throttle Control Motor ...........................................649
Injector ..................................................................650
Fuel Pump ............................................................650

EC-16Revision: August 2007
PRECAUTIONS
2004 QX56
PRECAUTIONSPFP:00001
Precautions for Supplemental Restraint System (SRS) “AIR BAG” and “SEAT
BELT PRE-TENSIONER”
UBS00GZ5
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.
WAR NIN G:

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.
On Board Diagnostic (OBD) System of Engine and A/TUBS00GZ6
The ECM has an on board diagnostic system. It will light up the malfunction indicator lamp (MIL) to warn the
driver of a malfunction causing emission deterioration.
CAUTION:

Be sure to turn the ignition switch OFF and disconnect the negative battery cable before any
repair or inspection work. The open/short circuit of related switches, sensors, solenoid valves,
etc. will cause the MIL to light up.

Be sure to connect and lock the connectors securely after work. A loose (unlocked) connector will
cause the MIL to light up due to the open circuit. (Be sure the connector is free from water, grease,
dirt, bent terminals, etc.)

Certain systems and components, especially those related to OBD, may use a new style slide-
locking type harness connector. For description and how to disconnect, refer to PG-68, "
HAR-
NESS CONNECTOR" .

Be sure to route and secure the harnesses properly after work. The interference of the harness
with a bracket, etc. may cause the MIL to light up due to the short circuit.

Be sure to connect rubber tubes properly after work. A misconnected or disconnected rubber tube
may cause the MIL to light up due to the malfunction of the EVAP system or fuel injection system,
etc.

Be sure to erase the unnecessary malfunction information (repairs completed) from the ECM and
TCM (Transmission control module) before returning the vehicle to the customer.
PrecautionUBS00GZ7

Always use a 12 volt battery as power source.

Do not attempt to disconnect battery cables while engine is
running.

Before connecting or disconnecting the ECM harness con-
nector, turn ignition switch OFF and disconnect negative
battery cable. Failure to do so may damage the ECM
because battery voltage is applied to ECM even if ignition
switch is turned OFF.

Before removing parts, turn ignition switch OFF and then
disconnect battery ground cable.
SEF 2 89 H

PRECAUTIONS
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EC
Revision: August 20072004 QX56

Do not disassemble ECM.

If a battery cable is disconnected, the memory will return to
the ECM value.
The ECM will now start to self-control at its initial value.
Engine operation can vary slightly when the terminal is dis-
connected. However, this is not an indication of a malfunc-
tion. Do not replace parts because of a slight variation.

When connecting ECM harness connector, fasten it
securely with a lever as far as it will go as shown in the fig-
ure.

When connecting or disconnecting pin connectors into or
from ECM, take care not to damage pin terminals (bend or
break).
Make sure that there are not any bends or breaks on ECM
pin terminal, when connecting pin connectors.

Securely connect ECM harness connectors.
A poor connection can cause an extremely high (surge)
voltage to develop in coil and condenser, thus resulting in
damage to ICs.

Keep engine control system harness at least 10 cm (4 in)
away from adjacent harness, to prevent engine control sys-
tem malfunctions due to receiving external noise, degraded
operation of ICs, etc.

Keep engine control system parts and harness dry.

Before replacing ECM, perform ECM Terminals and Refer-
ence Value inspection and make sure ECM functions prop-
erly. Refer to EC-96, "
ECM Terminals and Reference Value"
.

Handle mass air flow sensor carefully to avoid damage.

Do not disassemble mass air flow sensor.

Do not clean mass air flow sensor with any type of deter-
gent.

Do not disassemble electric throttle control actuator.

Even a slight leak in the air intake system can cause seri-
ous incidents.

Do not shock or jar the camshaft position sensor (PHASE), crankshaft position sensor (POS).
PBIB11 64 E
BBIA0387E
PBIB0090E
MEF040D

PRECAUTIONS
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EC
Revision: August 20072004 QX56

Do not operate fuel pump when there is no fuel in lines.

Tighten fuel hose clamps to the specified torque.

Do not depress accelerator pedal when starting.

Immediately after starting, do not rev up engine unneces-
sarily.

Do not rev up engine just prior to shutdown.

When installing C.B. ham radio or a mobile phone, be sure
to observe the following as it may adversely affect elec-
tronic control systems depending on installation location.
–Keep the antenna as far as possible from the electronic
control units.
–Keep the antenna feeder line more than 20 cm (8 in) away
from the harness of electronic controls.
Do not let them run parallel for a long distance.
–Adjust the antenna and feeder line so that the standing-
wave radio can be kept smaller.
–Be sure to ground the radio to vehicle body.
Wiring Diagrams and Trouble DiagnosisUBS00GZ8
When you read wiring diagrams, refer to the following:

GI-15, "How to Read Wiring Diagrams"

PG-4, "POWER SUPPLY ROUTING CIRCUIT" for power distribution circuit
When you perform trouble diagnosis, refer to the following:

GI-11, "HOW TO FOLLOW TEST GROUPS IN TROUBLE DIAGNOSES"

GI-27, "How to Perform Efficient Diagnosis for an Electrical Incident"
BBIA0402E
SEF 7 09 Y
SEF 7 08 Y

EC-20Revision: August 2007
PREPARATION
2004 QX56
PREPARATIONPFP:00002
Special Service ToolsUBS00GZ9
The actual shapes of Kent-Moore tools may differ from those of special service tools illustrated here.
Tool number
(Kent-Moore No.)
Tool nameDescription
EG17650301
(J-33984-A)
Radiator cap tester
adapterAdapting radiator cap tester to radiator cap and ra-
diator filler neck
a: 28 (1.10) dia.
b: 31.4 (1.236) dia.
c: 41.3 (1.626) dia.
Unit: mm (in)
KV10117100
(J-36471-A)
Heated oxygen sensor
wrenchLoosening or tightening heated oxygen sensors
with 22 mm (0.87 in) hexagon nut
KV10114400
(J-38365)
Heated oxygen sensor
wrenchLoosening or tightening heated oxygen sensors
a: 22 mm (0.87 in)
(J-44626)
Air fuel ratio (A/F) sen-
sor wrenchLoosening or tightening air fuel ratio (A/F) sensor 1
(J-44321)
Fuel pressure gauge
kitChecking fuel pressure
(J-44321-6)
Fuel pressure adapterConnecting fuel pressure gauge to quick connec-
tor type fuel lines.
(J-45488)
Quick connector re-
leaseRemove fuel tube quick connectors in engine
room.
S-NT564
S-NT379
S-NT636
LEM054
LEC642
LBIA0376E
PBIC0198E