2004 INFINITI QX56 cruise control

TROUBLE DIAGNOSIS
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Revision: August 20072004 QX56
NOTE:

Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.
DATA MONITOR (SPEC) MODE
Monitored Item
NOTE:
Any monitored item that does not match the vehicle being diagnosed is deleted from the display automatically.AT O D M O N I T O R
[ON/OFF]

Indicates [ON/OFF] condition of A/T O/D
according to the input signal from TCM.
AT OD CANCEL
[ON/OFF]

Indicates [ON/OFF] condition of A/T O/D can-
cel signal from TCM.
CRUISE LAMP
[ON/OFF]

Indicates [ON/OFF] condition of CRUISE lamp
determined by the ECM according to the input
signals.
SET LAMP
[ON/OFF]

Indicates [ON/OFF] condition of SET lamp
determined by the ECM according to the input
signals.
Voltage [V]

Voltage, frequency, duty cycle or pulse width
measured by the probe.

Only “#” is displayed if item is unable
to be measured.

Figures with “#”s are temporary ones.
They are the same figures as an actual
piece of data which was just previously
measured. Frequency [msec],
[Hz] or [%]
DUTY-HI
DUTY-LOW
PLS WIDTH-HI
PLS WIDTH-LOWMonitored item
[Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks
Monitored item [Unit]ECM
INPUT
SIG-
NALSMAIN
SIG-
NALSDescription Remarks
ENG SPEED [rpm]××

Indicates the engine speed computed
from the signal of the crankshaft position
sensor (POS).
MAS A/F SE-B1 [V]××

The signal voltage of the mass air flow
sensor specification is displayed.
When engine is running specification
range is indicated.
B/FUEL SCHDL
[msec]×

“Base fuel schedule” indicates the fuel
injection pulse width programmed into
ECM, prior to any learned on board cor-
rection.

When engine is running specification
range is indicated.
A/F ALPHA-B1 [%]
A/F ALPHA-B2 [%]×

The mean value of the air-fuel ratio feed-
back correction factor per cycle is indi-
cated.
When engine is running specification
range is indicated.

This data also includes the data for the
air-fuel ratio learning control.

EC-628Revision: August 2007
ASCD INDICATOR
2004 QX56
ASCD INDICATORPFP:24814
Component DescriptionUBS00HDT
ASCD indicator lamp illuminates to indicate ASCD operation status. Lamp has two indicators, CRUISE and
SET, and is integrated in combination meter.
CRUISE indicator illuminates when ON/OFF switch on ASCD steering switch is turned ON to indicated that
ASCD system is ready for operation.
SET indicator illuminates when following conditions are met.

CRUISE indicator is illuminated.

SET switch on ASCD steering switch is turned ON while vehicle speed is within the range of ASCD set-
ting.
SET indicator remains lit during ASCD control.
Refer to EC-647, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)" for the ASCD function.
CONSULT-II Reference Value in Data Monitor ModeUBS00HDU
Specification data are reference value.
MONITOR ITEM CONDITION SPECIFICATION
CRUISE LAMP

Ignition switch: ON
ON/OFF(MAIN) switch: Pressed
at the 1st time → at the 2nd timeON → OFF
SET LAMP

ON/OFF switch: ON

When vehicle speed is
between 40 km/h (25 MPH)
and 144 km/h (89 MPH)

COAST/SET switch: Pressed ON

COAST/SET switch: Released OFF

AUTOMATIC SPEED CONTROL DEVICE (ASCD)
EC-647
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Revision: August 20072004 QX56
AUTOMATIC SPEED CONTROL DEVICE (ASCD)PFP:18930
System DescriptionUBS00HE7
INPUT/OUTPUT SIGNAL CHART
*: This signal is sent to the ECM through CAN communication line.
BASIC ASCD SYSTEM
Refer to Owner's Manual for ASCD operating instructions.
Automatic Speed Control Device (ASCD) allows a driver to keep vehicle at predetermined constant speed
without pressing accelerator pedal. Driver can set vehicle speed in advance between approximately 40 km/h
(25 MPH) and 144 km/h (89 MPH).
ECM controls throttle angle of electric throttle control actuator to regulate engine speed.
Operation status of ASCD is indicated by CRUISE indicator and SET indicator in combination meter. If any
malfunction occurs in ASCD system, it automatically deactivates control.
SET OPERATION
Press ON/OFF(MAIN) switch. (The CRUISE indicator in combination meter illuminates.)
When vehicle speed reaches a desired speed between approximately 40 km/h (25 MPH) and 144 km/h (89
MPH), press COAST/SET switch. (Then SET indicator in combination meter illuminates.)
ACCEL OPERATION
If the ACCEL/RESUME switch is pressed during cruise control driving, increase the vehicle speed until the
switch is released or vehicle speed reaches maximum speed controlled by the system.
And then ASCD will keep the new set speed.
CANCEL OPERATION
When any of following conditions exist, cruise operation will be canceled.

CANCEL switch is pressed

More than 2 switches at ASCD steering switch are pressed at the same time (Set speed will be cleared)

Brake pedal is depressed

Selector lever is changed to N, P, R position

Vehicle speed decreased to 13 km/h (8 MPH) lower than the set speed

VDC/TCS system is operated
When the ECM detects any of the following conditions, the ECM will cancel the cruise operation and inform
the driver by blinking indicator lamp.

Engine coolant temperature is slightly higher than the normal operating temperature, CRUISE lamp may
blink slowly.
When the engine coolant temperature decreases to the normal operating temperature, CRUISE lamp will
stop blinking and the cruise operation will be able to work by pressing COAST/SET switch or ACCEL/
RESUME switch.

Malfunction for some self-diagnoses regarding ASCD control: SET lamp will blink quickly.
If ON/OFF(MAIN) switch is turned to OFF during ASCD is activated, all of ASCD operations will be canceled
and vehicle speed memory will be erased.
COAST OPERATION
When the COAST/SET switch is pressed during cruise control driving, decrease vehicle set speed until the
switch is released. And then ASCD will keep the new set speed.
Sensor Input signal to ECM ECM function Actuator
ASCD brake switch Brake pedal operation
ASCD vehicle speed controlElectric throttle control
actuator Stop lamp switch Brake pedal operation
ASCD steering switch ASCD steering switch operation
Park/Neutral position (PNP)
switchGear position
Combination meter* Vehicle speed
TCM* Powertrain revolution

IDX-5
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IDX
ALPHABETICAL INDEX
H
H/AIM - Wiring diagram ...................................... LT-66
H/LAMP - Wiring diagram .................................. LT-10
Handling precautions for plastics ..................... BL-189
Harness connector ............................................ PG-68
Harness layout .................................................. PG-40
Hazard warning lamp ......................................... LT-80
Headlamp ............................................................. LT-6
Headlamp aiming control ................................... LT-65
Headlamp leveler - See Headlamp aiming control . LT-
65
Headlamp removal and installation .................... LT-33
Heated oxygen sensor 2 (bank 1) .... EC-186, EC-196,
EC-383
, EC-395
Heated oxygen sensor 2 (bank 2) .... EC-186, EC-196,
EC-383
, EC-395
Heated oxygen sensor 2 heater (bank 1) ........ EC-138
Heated oxygen sensor 2 heater (bank 2) ........ EC-138
Heated seat ....................................................... SE-89
Heater and cooling unit (Heater core) . ATC-144, ATC-
147
Heater unit (heater core) ............... ATC-144, ATC-147
Height (Dimensions) ........................................... GI-49
HFC134a (R134a) system identification ........... ATC-7
HFC134a (R134a) system precaution ............... ATC-5
HFC134a (R134a) system service procedure ATC-162
HFC134a (R134a) system service tools ......... ATC-14
HFC134a system service equipment precaution ATC-
11
High and low reverse clutch solenoid valve .... AT-163,
AT-166
Horn ................................................................ WW-56
HORN - Wiring diagram .................................. WW-56
How to erase DTC for OBD system .................. EC-62
HSEAT - Wiring diagram ................................... SE-91
I
I/MIRR - Wiring diagram ................................... GW-76
IATS - Wiring diagram ..................................... EC-162
ICC - Wiring diagram ....................................... ACS-20
ICC/BS - Wiring diagram ................................. EC-527
ICC/SW - Wiring diagram ................................ EC-512
ICCBOF - Wiring diagram ............................... EC-614
Identification plate .............................................. GI-47
Idle air volume learning ..................................... EC-44
Idle mixture ratio ................................................ EC-33
Idle speed .......................................................... EC-33
Idle speed control (ISC) .................... EC-342, EC-344
Ignition coil .......................................... EM-26, EC-583
Ignition control system .................................... EC-583
Ignition key hole illumination ............................ LT-129
Ignition timing .................................................... EC-33
IGNSYS - Wiring diagram ............................... EC-584
ILL - Wiring diagram ......................................... LT-158
Illumination ....................................................... LT-152
Illumination control .............................. LT-152, LT-169
In vehicle sensor ........................... ATC-128, ATC-137
In-cabin Microfilter ............................................. MA-20
INJECT - Wiring diagram ................................. EC-596
Injector ............................................................. EC-595
Input clutch solenoid valve ................. AT-145, AT-148
Instrument panel .................................................. IP-10
Instrument panel speaker .................................. AV-46
INT/L - Wiring diagram ..................................... LT-135
Intake air temperature sensor ............ EC-161, EC-181
Intake door control linkage adjustment . ATC-78, ATC-
80
Intake door motor ........................... ATC-76, ATC-151
Intake manifold .................................................. EM-15
Intake sensor ................................ ATC-133, ATC-139
Intelligent cruise control (ICC) system ............... ACS-6
Interior ................................................................. EI-34
Interior lamp ...................................................... LT-129
Interior lamp on-off control ................................ LT-129
Internal gear (Transfer) ..................................... TF-127
IPDM (Intelligent power distribution module engine
room) ................................................................. PG-17
IVIS (Infiniti vehicle immobilizer system) precautions ...
GI-3
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Jacking points ..................................................... GI-40
Junction box (J/B) .............................................. PG-76
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Key illumination ................................................ LT-129
Keyless entry system - See Multi-remote control system
BL-44
Knock sensor (KS) ........................................... EC-250
KS - Wiring diagram ........................................ EC-251
L
Length (Dimensions) .......................................... GI-49
License lamp .................................................... LT-108
Lifting points ....................................................... GI-41
Line pressure solenoid valve ........................... AT-124
Line pressure switch (Transfer) .......................... TF-95
Line pressure test (A/T) ..................................... AT-59
Liquid gasket application ......................... LU-2, FFD-2
Location of electrical units ................................. PG-64
Low coast brake solenoid valve .......... AT-169, AT-172
Low tire pressure warning system ...................... WT-7
Low tire pressure warning system - trouble diagnoses
WT-10
Low tire pressure warning system - Wiring diagram .....
WT-10
Lubricant (R134a) A/C ..................................... ATC-22
Lubricants .......................................................... MA-10
Lubrication circuit (engine) .................................. LU-5
Lubrication oil A/C ........................................... ATC-22
Lubrication-locks, hinges and hood latches ....... MA-30

LAN-6
[CAN]
CAN COMMUNICATION
Revision: August 20072004 QX56
Engine coolant temperature signal T R R R
A/T self-diagnosis signal R T
Accelerator pedal position signal T R R
Closed throttle position signal T R
Wide open throttle position signal T R
Battery voltage signal T R
Key switch signal R T
Ignition switch signal R T R
P range signal T R
Stop lamp switch signal R T R
Parking brake switch signal T R
Fuel consumption monitor signalTR
TR
Turbine revolution signal R T
Output shaft revolution signal R T
A/C switch signal R T
A/C compressor request signal T R R
Blower fan motor switch signal R T R
A/C switch/indicator signalTR
RT
Cooling fan speed request signal T R R
Position light request signal R T R
Low beam request signal T R
Low beam status signal RT
High beam request signal R T R
High beam status signal RT
Front fog light request signal T R
Day time running light request signal T R
Vehicle speed signalRRT
RRRTRR R
Sleep wake up signal R T R
Door switch signal R R R T R
Turn indicator signal R T
Key fob ID signal R T
Key fob door unlock signal R T
Buzzer output signal R T
Fuel level sensor signal R T
Fuel level low warning signal T R
ASCD SET lamp signal T R
ASCD CRUISE lamp signal T RSignals ECM TCMDriver
seat
con-
trol
unitCom-
bina-
tion
meterDis-
play
con-
trol
unitBCMStee r-
ing
angle
sensorFront
air
control ABS
actua-
tor and
elec-
tric unit
(con-
trol
unit)IPDM
E/R

LAN-12
[CAN]
CAN COMMUNICATION
Revision: August 20072004 QX56
Buzzer output signal R T
Fuel level sensor signal R T
ASCD SET lamp signal T R
ASCD CRUISE lamp signal T R
Malfunction indicator lamp signal T R
Fuel level low warning signal T R
Front wiper request signal T R
Front wiper stop position signal R T
Rear window defogger switch signal T R R
Rear window defogger control signal R R R T
Hood switch signal R T
Theft warning horn request signal T R
Horn chirp signal T R
Steering angle sensor signal T R
ABS warning lamp signal R T
VDC OFF indicator lamp signal R T
SLIP indicator lamp signal R T
Brake warning lamp signal R T
System setting signalRT
TR
Distance to empty signal T R
ASCD operation signal T R
ASCD OD cancel request T R
A/T CHECK indicator lamp signal T R
A/T position indicator lamp signal T R R
Tire pressure signal R T
Tire pressure data signal R T
1st position switch signal R T
4th position switch signal R T
Tow mode switch signal R T
A/T fluid temperature sensor signal T RSignals ECM TCMDriver
seat
con-
trol
unitCom-
bina-
tion
meterDis-
play
con-
trol
unitBCMSteer-
ing
angle
sen-
sorFront
air
con-
trolTrans-
fer
con-
trol
unitABS
actua-
tor
and
elec-
tric
unit
(con-
trol
unit)IPDM
E/R

PG-62
HARNESS
Revision: August 20072004 QX56
HSEAT SE Heated Seat
IATS EC Intake Air Temperature Sensor
ICC ACS Intelligent Cruise Control
ICCBOF EC ICC Brake Switch
ICC/BS EC ICC Steering Switch
ICC/SW EC ICC Brake Switch
I/MIRR GW Inside Mirror (Auto Anti-Dazzling Mirror)
IGNSYS EC Ignition System
ILL LT Illumination
INJECT EC Injector
INT/L LT Room/Map, Vanity, Cargo, Personal, Foot, Step, and Puddle Lamps
KEYLES BL Remote Keyless Entry System
KS EC Knock Sensor
MAFS EC Mass Air Flow Sensor
MAIN EC Main Power Supply and Ground Circuit
METER DI Speedometer, Tachometer, Temp. and Fuel Gauges
MIL/DL EC Malfunction Indicator Lamp
MIRROR GW Door Mirror
NATS BL Nissan Anti-Theft System
NAVI AV Navigation System
O2H2B1 EC Rear Heated Oxygen Sensor 2 Heater Bank 1
O2H2B2 EC Rear Heated Oxygen Sensor 2 Heater Bank 2
O2S2B1 EC Heated Oxygen Sensor 2 Bank 1
O2S2B2 EC Heated Oxygen Sensor 2 Bank 2
P/SCKT WW Power Socket
PGC/V EC EVAP Canister Purge Volume Control Solenoid Valve
PHASE EC Camshaft Position Sensor (PHASE) (Bank 1)
PNP/SW EC Park/Neutral Position Switch
POS EC Crankshaft Position Sensor (POS)
POWER PG Power Supply Routing
PRE/SE EC EVAP Control System Pressure Sensor
PS/SEN EC Power Steering Pressure Sensor
R/VIEW DI Rear View Monitor
RP/SEN EC Refrigerant Pressure Sensor
SEAT SE Power Seat (Without Memory)
SEN/PW EC Sensor Power Supply
SHIFT AT A/T Shift Lock System
SONAR DI Rear Sonar System
SROOF RF Sunroof
SRS SRS Supplemental Restraint System
START SC Starting System
STOP/L LT Stop Lamp
T/TOW LT Trailer Tow
T/WARN WT Low Tire Pressure Warning System
TAIL/L LT Parking, License and Tail Lamps
T/F TF Transfer Case
TPS1 EC Throttle Position Sensor
TPS2 EC Throttle Position Sensor
TPS3 EC Throttle Position Sensor
TRNSCV BL HOMELINK® Universal Transceiver
TURN LT Turn Signal and Hazard Warning Lamps
VDC BRC Vehicle Dynamic Control System

TF-1
TRANSFER
D DRIVELINE/AXLE
CONTENTS
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SECTION TF
A
B
TF
Revision: August 20072004 QX56 PREPARATION ........................................................... 4
Special Service Tools ............................................... 4
Commercial Service Tools ........................................ 7
PRECAUTIONS .......................................................... 8
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 8
Precautions .............................................................. 8
Service Notice .......................................................... 9
Wiring Diagrams and Trouble Diagnosis .................. 9
ALL-MODE 4WD SYSTEM ...................................... 10
Cross-sectional View .............................................. 10
Control System ........................................................11
ALL-MODE 4WD TRANSFER BASIC CONTROL
... 12
HYDRAULIC CONTROL CIRCUITS ................... 12
OUTLINE ............................................................. 12
CONTROL SYSTEM DIAGRAM ......................... 13
INDICATIONS OF 4WD WARNING LAMP ......... 13
CAN Communication .............................................. 13
SYSTEM DESCRIPTION .................................... 13
Location of Electrical Parts ..................................... 14
Description of Electrical Parts ................................ 15
TRANSFER MOTOR .......................................... 15
WAIT DETECTION SWITCH .............................. 15
2-4WD SHIFT SOLENOID VALVE ...................... 15
LINE PRESSURE SWITCH ................................ 16
Circuit Diagram for Quick Pinpoint Check .............. 17
Wiring Diagram — T/F — ....................................... 18
ON BOARD DIAGNOSTIC SYSTEM DESCRIP-
TION .......................................................................... 27
Trouble Diagnosis without CONSULT-II ................. 27
DESCRIPTION .................................................... 27
SELF-DIAGNOSTIC PROCEDURE .................... 28
INDICATIONS OF 4WD WARNING LAMP ......... 28CONSULT-II Function (ALL MODE AWD/4WD) ..... 31
Trouble Diagnosis with CONSULT-II ...................... 31
SELF-DIAGNOSIS .............................................. 31
SELF-DIAGNOSTIC ITEMS ................................ 32
DATA MONITOR ................................................. 34
DATA MONITOR ITEMS ..................................... 35
REFERENCE VALUE IN DATA MONITOR MODE
... 38
WORK SUPPORT ............................................... 41
CLUTCH FORCE RELEASE LIMIT ADJUST-
MENT .................................................................. 42
TROUBLE DIAGNOSIS — INTRODUCTION ........... 44
Introduction ............................................................. 44
DESCRIPTION .................................................... 44
DIAGNOSTIC WORKSHEET .............................. 44
Work Flow ............................................................... 46
HOW TO PERFORM TROUBLE DIAGNOSES
FOR QUICK AND ACCURATE REPAIR ............. 46
TROUBLE DIAGNOSIS — BASIC INSPECTION .... 47
Listen to Customer Complaints .............................. 47
Transfer Fluid Check .............................................. 47
Road Test ............................................................... 47
PREPARATION FOR ROAD TEST ..................... 47
1. CHECK BEFORE ENGINE IS STARTED ....... 48
2. CHECK AT IDLE .............................................. 49
3. CRUISE TEST ................................................. 53
TROUBLE DIAGNOSIS — GENERAL DESCRIP-
TION .......................................................................... 55
Transfer Control Unit Terminals and Reference
Value ....................................................................... 55
TRANSFER CONTROL UNIT HARNESS CON-
NECTOR LAYOUT .............................................. 55
TRANSFER CONTROL UNIT INSPECTION
TABLE ................................................................. 55
DTC U1000, U1001 CAN COMMUNICATION LINE ... 59
CAN Communication System Inspection ................ 59
4WD SOLENOID VALVE .......................................... 60
Diagnostic Procedure ............................................. 60
2-4WD SHIFT SOLENOID VALVE AND 4WD SHIFT