2004 INFINITI QX56 fuel pressure

COMBINATION METERS
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Revision: August 20072004 QX56
COMBINATION METERSPFP:24814
System DescriptionEKS007DL
UNIFIED METER CONTROL UNIT

Speedometer, odometer, tachometer, fuel gauge, oil pressure gauge, voltage meter, A/T temperature
gauge, and water temperature gauge are controlled by the unified meter control unit, which is built into the
combination meter.

Warning indicators are controlled by signals drawn from the CAN communication system, BCM (body con-
trol module), and components connected directly to the combination meter.

Digital meter is adopted for odometer/trip meters*, as well as the A/T position indicator display.
*The record of the odometer is kept even if the battery cable is disconnected.

Odometer/trip meters and A/T indicator segments can be checked in diagnosis mode.

Meters/gauges can be checked in diagnosis mode.
Illumination control
The unified meter control unit outputs the speedometer, odometer/trip meters, tachometer, oil pressure gauge,
voltage meter, A/T indicator, A/T temperature gauge, fuel and temperature gauge lighting when the ignition
switch is turned on. When the lighting switch is turned on, the illumination control switch can be used to adjust
the brightness of the combination meter illumination and the odometer/trip meters and meter illumination.
When the ignition switch is turned from the OFF to the ON position, the combination meter dial lighting will
remain off for 0.7 seconds. For additional combination meter illumination control information, refer to LT-152,
"System Description" .

DI-6
COMBINATION METERS
Revision: August 20072004 QX56
POWER SUPPLY AND GROUND CIRCUIT
Power is supplied at all times

through 10A fuse [No.19, located in the fuse block (J/B)]

to combination meter terminal 8.
With the ignition switch in the ON or START position, power is supplied

through 10A fuse [No.14, located in the fuse block (J/B)]

to combination meter terminal 24.
With the ignition switch in the ACC or ON position, power is supplied

through 10A fuse [No.4, located in the fuse block (J/B)]

to combination meter terminal 1.
Ground is supplied

to combination meter terminal 17

through body grounds M57, M61 and M79.
WATER TEMPERATURE GAUGE
The water temperature gauge indicates the engine coolant temperature.
ECM provides an engine coolant temperature signal to combination meter via CAN communication lines.
ENGINE OIL PRESSURE GAUGE
The engine oil pressure gauge indicates the engine oil pressure.
The engine oil pressure gauge is regulated by the unified meter control unit and input from the oil pressure
sensor.
A/T OIL TEMPERATURE GAUGE
The A/T oil temperature gauge indicates the A/T fluid temperature.
TCM (transmission control module) provides an A/T fluid temperature signal to combination meter via CAN
communication lines.
V O LTA G E G A U G E
The voltage gauge indicates the battery/charging system voltage.
The voltage gauge is regulated by the unified meter control unit.
TACHOMETER
The tachometer indicates engine speed in revolutions per minute (rpm).
ECM provides an engine speed signal to combination meter via CAN communication lines.
FUEL GAUGE
The fuel gauge indicates the approximate fuel level in the fuel tank.
The fuel gauge is regulated by the unified meter control unit and a variable resistor signal supplied

to combination meter terminal 15.

through fuel level sensor unit and fuel pump terminal 2

through fuel level sensor unit and fuel pump terminal 5

from combination meter terminal 16
SPEEDOMETER
ABS actuator and electric unit (control unit) provides a vehicle speed signal to the combination meter via CAN
communication lines.
CAN COMMUNICATION SYSTEM DESCRIPTION
Refer to LAN-5, "CAN COMMUNICATION" .

DI-12
COMBINATION METERS
Revision: August 20072004 QX56
Terminals and Reference Value for Combination MeterEKS007DQ
Te r m i n a l
No.Wire
colorItemCondition
Reference value (V)
(Approx.) Ignition
switchOperation or condition
1OIgnition switch ACC or
ONACC — Battery voltage
8 Y/R Battery power supply OFF — Battery voltage
11 W C A N - H — — —
12 R CAN-L — — —
15 Y/L Fuel level sensor signal — —Refer to DI-22, "
Fuel Level Sensor
Unit Inspection" .
16 B/PFuel level sensor and oil
pressure sensor groundON — 0V
17 B Ground OFF — 0V
18 BR Illumination control switch — Lighting switch ONRefer to LT-153, "
ILLUMINATION
OPERATION BY LIGHTING
SWITCH" .
20 YOil pressure sensor sig-
nalON — 0 - 5V
22 GR/LOil pressure sensor refer-
ence voltageON — 5V
24 O/LIgnition switch ON or
STARTON — Battery voltage

DI-14
COMBINATION METERS
Revision: August 20072004 QX56
Next test requested Sc1XXDisplays 8-bit software
configuration value in Hex
format.Bit Coding
7-3 = reserved for future use
2 = TCS/VDC 0 = not present
1 = present
1 = Shift type 0 = Column shift
1 = Floor shift
0 = ICC 0 = not present
1 = present
Next test requested Sc2XXDisplays 8-bit software
configuration value in Hex
format.Bit coding
7-0 = Reserved for future use
Next test requested EprXXDisplays 8-bit software
configuration value in Hex
format.Bit Coding
7-2 = reserved for future use
1 = A/T Oil Temp (gauge)
0 = not present
1 = present
1 = Odo Units 0 = kilometers
1 = miles
Next test requested 1nFXXDisplays 8-bit market info
value in Hex format.$31 = USA
$2A = Canada
Next test requested cYLXXDisplays 8-bit engine con-
figuration value in Hex
format.$08 = 8 cylinder
$06 = 6 cylinder
Next test requested FFXXXXDisplays 16-bit fuel flow
constant "Q" in tenths of
cc/min in Hex format.$0000 - $FFFF
Next test requested tFDisplays 16-bit tire factor
"A" in hundredths in Hex
format.$0000 - $FFFF
Next test requested ot1XXDisplays oil pressure tell-
tale "on" threshold in A/D
counts in Hex format.$00 - $FF
Next test requested ot0XXDisplays oil pressure tell-
tale "off" threshold in A/D
counts in Hex format.$00 - $FF
Next test requested XXXXXRaw uncompensated
english speed value in
hundredths of MPH.
Speedometer indicates
present speed.Will display "-----" if message is
not received. Will display
"99999" if data received is
invalid
Next test requested XXXXXRaw uncompensated
metric speed value in
hundredths of KPH.
Speedometer indicates
present speed.Will display "-----" if message is
not received. Will display
"99999" if data received is
invalid
Next test requested tXXXXTachometer value in
RPM. Tachometer indi-
cates present RPM.Will display "-----" if message is
not received.
Next test requested F1 XXXXPresent ratioed fuel level
A/D input 1 in decimal for-
mat. Fuel gauge indicates
present filtered level.000-009 = Short circuit
010-254 = Normal range
255 = Open circuit
--- = Missing 5 seconds
Next test requested XXXCLast temperature gauge
input value in degrees C.
Temperature gauge indi-
cates present filtered tem-
perature.Will display "---"C if message is
not received.
Will display "999" if data
received is invalid. Event Odometer Display Description of Test/Data Notes:

COMBINATION METERS
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Revision: August 20072004 QX56
Symptom ChartEKS007DV
Vehicle Speed Signal InspectionEKS007DW
1. CHECK ABS ACTUATOR AND ELECTRIC UNIT (CONTROL UNIT) SELF-DIAGNOSIS
Refer to BRC-29, "
SELF-DIAGNOSIS" .
OK or NG
OK >> Replace the combination meter. Refer to IP-13, "Combination Meter" .
NG >> Perform the "Diagnostic Procedure" for displayed DTC. Refer to BRC-11, "
TROUBLE DIAGNO-
SIS" .
Engine Oil Pressure Signal Inspection EKS0086D
1. CHECK OIL PRESSURE SENSOR SIGNAL
1. Turn ignition switch ON.
2. Check voltage between combination meter harness connector
M24 terminal 20 (Y) and ground.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
Trouble phenomenon Possible cause
Improper tachometer indication. Refer to DI-21, "
Engine Speed Signal Inspection" .
Improper water temperature gauge indication. Refer to DI-21, "
Water Temperature Signal Inspection" .
Improper speedometer or odometer. Refer to DI-19, "
Vehicle Speed Signal Inspection" .
Improper fuel gauge indication.
Refer to DI-22, "
Fuel Level Sensor Unit Inspection" .
Fuel warning lamp indication is irregular.
Improper A/T oil temperature gauge indicationRefer to AT-131, "
DTC P1710 A/T FLUID TEMPERATURE SEN-
SOR CIRCUIT" .
Improper voltage gauge indication
Replace combination meter. Refer to IP-13, "
Combination Meter"
.
More than one gauge does not give proper indication.
Improper A/T position indication. Refer to DI-41, "
A/T INDICATOR" .
Illumination control does not operate properly. Refer to LT-152, "
ILLUMINATION" .
Te r m i n a l s
Condition Voltage (V) (+)
(–)
ConnectorTe r m i n a l
(Wire color)
M24 20 (Y) GroundWhen ignition switch is in ON
position. (Engine stopped)Ye s
Engine running. (Idle speed) Yes
WKIA1833E

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

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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-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