2004 INFINITI QX56 brake light

ASCD BRAKE SWITCH
EC-623
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Revision: August 20072004 QX56
Specification data are reference values and are measured between each terminal and ground.
CAUTION:
Do not use ECM ground terminals when measuring input/output voltage. Doing so may result in dam-
age to the ECM's transistor. Use a ground other than ECM terminals, such as the ground.
Diagnostic ProcedureUBS00HDR
1. CHECK OVERALL FUNCTION-I
With CONSULT-II
1. Turn ignition switch ON.
2. Select “BRAKE SW1” in “DATA MONITOR” mode with CONSULT-II.
3. Check “BRAKE SW1” indication under the following conditions.
Without CONSULT-II
1. Turn ignition switch ON.
2. Check voltage between ECM terminal 108 and ground under the
following conditions.
OK or NG
OK >> GO TO 2.
NG >> GO TO 3.
TER-
MINAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
101 R/W Stop lamp switch[Ignition switch: ON]

Brake pedal: Fully releasedApproximately 0V
[Ignition switch: ON]

Brake pedal: Slightly depressedBATTERY VOLTAGE
(11 - 14V)
108 BR/W ASCD brake switch[Ignition switch: ON]

Brake pedal: Slightly depressedApproximately 0V
[Ignition switch: ON]

Brake pedal: Fully releasedBATTERY VOLTAGE
(11 - 14V)
CONDITION INDICATION
When brake pedal is depressed OFF
When brake pedal is fully released ON
SEC0 11D
CONDITION VOLTAGE
When brake pedal is depressed Approximately 0V
When brake pedal is fully released Battery voltage
MBIB0061E

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-3
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IDX
ALPHABETICAL INDEX
Brake lines and cables inspection ..................... MA-27
Brake master cylinder ....................................... BR-15
Brake switch .................................................... EC-551
BRK/SW - Wiring diagram ............................... EC-552
Bulb specifications ........................................... LT-170
Bumper, front ...................................................... EI-13
Bumper, rear ....................................................... EI-15
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Cabin air filter .................................................... MA-20
Camshaft ........................................................... EM-43
Camshaft inspection .......................................... EM-47
Camshaft position sensor (PHASE) ................ EC-261
CAN - Wiring diagram EC-136, LAN-18, LAN-52, LAN-
92, LAN-128
CAN (Controller Area Network) .. WT-9, BRC-10, LAN-
16, LAN-50, LAN-90, LAN-126
CAN communication . EC-31, EC-135, AT-103, WT-9,
BRC-10
, LAN-16, LAN-50, LAN-90, LAN-126
Canister-See EVAP canister ........................... EC-636
Center case (Transfer) ..................................... TF-113
CHARGE - Wiring diagram ............................... SC-18
Charging system ............................................... SC-17
Chassis and body maintenance ........................ MA-20
Chassis and body maintenanceSchedule 1 ........ MA-7
Chassis and body maintenanceSchedule 2 ........ MA-9
CHIME - Wiring diagram ..................................... DI-46
Circuit breaker ................................................... PG-67
Clock ................................................................... DI-70
CLOCK - Wiring diagram .................................... DI-70
Closed loop control ........................................... EC-27
Closed loop control (Bank 1) ........................... EC-407
Closed loop control (Bank 2) ........................... EC-407
Clutch drum (Transfer) ..................................... TF-116
Clutch force release limit adjustment ................. TF-42
Clutch pressure switch (Transfer) ...................... TF-95
Coil spring (front) ............................................. FSU-10
Collision diagnosis .......................................... SRS-60
Combination lamp, front, removal and installation . LT-
33
Combination lamp, rear, removal and installation .. LT-
122
Combination meter ................................................ DI-5
Combination switch ............................................ LT-97
COMBSW - Wiring diagram ............................... LT-97
COMM - Wiring diagram ................................... AV-87
COMPAS - Wiring diagram ................................. DI-27
Compass ............................................................. DI-26
Component Location (auto A/C) ...................... ATC-37
Compressor clutch removal and installation . ATC-167
Compressor mounting ................................... ATC-166
Compressor precaution ................................... ATC-11
Compressor special service tool ..................... ATC-14
Condenser ..................................................... ATC-173
Connecting rod .................................................. EM-91
Connecting rod bearing clearance .................... EM-91
Connecting rod bushing clearance .................... EM-91
Console box - See Instrument panel ................... IP-10
Console box lamp ............................................. LT-152
CONSULT for all-mode 4WD ............................. TF-31
CONSULT for VDC ......................................... BRC-28
CONSULT-II for engine ................................... EC-103
Control units (terminal arrangement) ................. PG-71
Control valve (A/T) ............................................. AT-37
Control valve (Transfer) .................................... TF-119
Controller Area Network (CAN) . WT-9, BRC-10, LAN-
16, LAN-50, LAN-90, LAN-126
Converter housing installation ............ AT-257, AT-260
COOL/F - Wiring diagram ................................ EC-413
Coolant mixture ratio ......................................... MA-11
Coolant replacement ......................................... MA-12
Cooling circuit (engine) ........................................ CO-6
Cooling fan ........................................................ CO-13
Cooling fan control ........................................... EC-410
Cooling fan motor ............................................ EC-419
Cooling unit (A/C evaporator) ....... ATC-144, ATC-175
Corrosion protection ......................................... BL-167
Crankcase ventilation system - See Positive crankcase
ventilation ........................................................ EC-645
Crankshaft ......................................................... EM-74
Crankshaft position sensor (POS) ................... EC-255
Crash zone sensor .......................................... SRS-55
Cylinder block .................................................... EM-73
Cylinder block boring ......................................... EM-94
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D/LOCK - Wiring diagram ................................... BL-20
Data link connector .......................................... EC-105
Daytime light system .......................................... LT-34
Daytime running light - See Daytime light system .. LT-
34
DEF - Wiring diagram ....................................... GW-82
Diagnosis sensor unit ...................................... SRS-58
Diagnostic trouble code (DTC) .......................... EC-53
Diagnostic trouble code (DTC) for OBD system .. EC-8
Diagnostic trouble code (DTC) inspection priority chart
EC-76
Differential carrier assembly ............................ RFD-11
Differential carrier disassembly ....................... RFD-13
Differential gear oil replacement ........................ MA-25
Dimensions ......................................................... GI-49
Direct clutch solenoid valve ................ AT-157, AT-160
Display and amp.assembly .............................. ATC-60
Display Control Unit ......................................... AV-158
Dome light - See Interior lamp .......................... LT-129
Door glass .......................................... GW-69, GW-72
Door lock .......................................................... BL-132
Door mirror lamp ............................................... LT-129
Door trim .............................................................. EI-31
Door, front ........................................... BL-129, GW-69
Door, rear ........................................... BL-129, GW-72
Drive belt ........................................................... EM-12
Drive chain (Transfer) ....................................... TF-115
Drive pinion diff. inspection .............................. RFD-12
Drive pinion height ........................................... RFD-17
Drive shaft (rear) ................................................ RAX-7

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

CAN COMMUNICATION
LAN-9
[CAN]
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LAN
Revision: August 20072004 QX56
A/C switch/indicator signalTR
RT
Cooling fan speed request signal T R R
Position light request signal R T R
Low beam request signalTR
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
RR R R T R R 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 signalRT
TR
Fuel level sensor signal R T
Fuel level low warning signal T R
Malfunction indicator lamp signal T R
Front wiper request signal R T R
Front wiper stop position signal R T
Rear window defogger switch signal T R R
Rear window defogger control signal R R T
Hood switch signalRT
Theft warning horn request signal T R
Horn chirp signalTR
Steering angle sensor signalTR
ABS warning lamp signal R T
VDC OFF indicator lamp signal R R T
SLIP indicator lamp signal R T
Brake warning lamp signal R T
VDC operation signal R T
ABS malfunction signal R T
TCS malfunction signal R T
VDC malfunction signal R TSignals ECM TCMICC
sen-
sorICC
unitDriver
seat
con-
trol
unitCom-
bina-
tion
mete
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play
con-
trol
unitBCMSteer-
ing
angle
sensorFront
air
con-
trol ABS
actu-
ator
and
elec-
tric
unit
(con-
trol
unit)IPD
M E/
R

CAN COMMUNICATION
LAN-11
[CAN]
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LAN
Revision: August 20072004 QX56
Input/output signal chart
T: Transmit R: Receive
Signals ECM TCMDriver
seat
con-
trol
unitCom-
bina-
tion
meterDis-
play
con-
trol
unitBCMStee r-
ing
angle
sen-
sorFront
air
con-
trolTran s-
fer
con-
trol
unitABS
actua-
tor
and
elec-
tric
unit
(con-
trol
unit)IPDM
E/R
A/T self-diagnosis signal R T
Stop lamp switch signal R T R
Parking brake switch signal T R
Battery voltage signal T R
Key switch signal R T
Ignition switch signal R T R
P range signal T R
Closed throttle position signal T R
Wide open throttle position signal T R
Engine speed signal T R R R R R
Engine status signal T R R
Engine coolant temperature signal T R R R
Accelerator pedal position signal T R R R
Fuel consumption monitor signalTR
TR
Turbine revolution signal R T
Output shaft revolution signal R T R
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 signalRRRT
RRRT RR 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

LAN-14
[CAN]
CAN COMMUNICATION
Revision: August 20072004 QX56
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
signalTR
Vehicle speed signalR RRT
RRR R T R R 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 signalRT
TR
Fuel level sensor signal R T
Malfunction indicator lamp signal T R
Fuel level low warning signal T R
Front wiper request signal R T R
Front wiper stop position signal R T
Rear window defogger switch sig-
nalTR R
Rear window defogger control
signalRRRT
Hood switch signalRT
Theft warning horn request signal T R
Horn chirp signalTR
Steering angle sensor signal T R
ABS warning lamp signal R T
VDC OFF indicator lamp signal R R T
SLIP indicator lamp signal R T
Brake warning lamp signal R T
VDC operation signal R T
ABS malfunction signal R TSignals ECM TCMICC
sen-
sorICC
unitDriver
seat
con-
trol
unitCom-
bina-
tion
mete
rDis-
play
con-
trol
unitBCMStee r-
ing
angle
sen-
sorFront
air
con-
trolTran s -
fer
con-
trol
unitABS
actu-
ator
and
elec-
tric
unit
(con-
trol
unit)IPD
M
E/R

LT-1
LIGHTING SYSTEM
K ELECTRICAL
CONTENTS
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SECTION LT
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LT
Revision: August 20072004 QX56 PRECAUTIONS .......................................................... 4
Precautions for Supplemental Restraint System
(SRS) “AIR BAG” and “SEAT BELT PRE-TEN-
SIONER” .................................................................. 4
General precautions for service operations ............. 5
Wiring Diagrams and Trouble Diagnosis .................. 5
HEADLAMP (FOR USA) ............................................ 6
Component Parts and Harness Connector Location ..... 6
System Description .................................................. 6
OUTLINE ............................................................... 6
XENON HEADLAMP ............................................. 7
BATTERY SAVER CONTROL .............................. 8
AUTO LIGHT OPERATION ................................... 8
VEHICLE SECURITY SYSTEM (PANIC ALARM) ..... 8
CAN Communication System Description ................ 8
Schematic ................................................................ 9
Wiring Diagram — H/LAMP — ............................... 10
Terminals and Reference Values for BCM ............. 14
Terminals and Reference Values for IPDM E/R ..... 15
How to Proceed With Trouble Diagnosis ................ 15
Preliminary Check .................................................. 16
CHECK POWER SUPPLY AND GROUND CIR-
CUIT .................................................................... 16
CONSULT-II Function (BCM) ................................. 18
CONSULT-II OPERATION .................................. 18
WORK SUPPORT ............................................... 19
DATA MONITOR ................................................. 19
ACTIVE TEST ..................................................... 20
SELF-DIAGNOSTIC RESULTS .......................... 20
CONSULT-II Function (IPDM E/R) ......................... 21
CONSULT-II OPERATION .................................. 21
DATA MONITOR ................................................. 22
ACTIVE TEST ..................................................... 22
Headlamp HI Does Not Illuminate (Both Sides) ..... 23
Headlamp HI Does Not Illuminate (One Side) ....... 25
High Beam Indicator Lamp Does Not Illuminate .... 26
Headlamp LO Does Not Illuminate (Both Sides) .... 26
Headlamp LO Does Not Illuminate (One Side) ...... 28
Headlamps Do Not Turn OFF ................................ 29
Aiming Adjustment ................................................. 31LOW BEAM AND HIGH BEAM ........................... 31
Bulb Replacement .................................................. 32
HEADLAMP (OUTER SIDE), FOR LOW BEAM ... 32
HEADLAMP (INNER SIDE), FOR HIGH BEAM ... 32
FRONT PARKING LAMP (INNER OR OUTER) ... 32
FRONT SIDE MARKER LAMP ........................... 32
Removal and Installation ........................................ 33
REMOVAL ........................................................... 33
INSTALLATION ................................................... 33
Disassembly and Assembly .................................... 33
HEADLAMP (FOR CANADA) - DAYTIME LIGHT
SYSTEM - .................................................................. 34
Component Parts and Harness Connector Location ... 34
System Description ................................................. 35
OUTLINE ............................................................. 35
DAYTIME LIGHT OPERATION ........................... 35
COMBINATION SWITCH READING FUNCTION ... 35
AUTO LIGHT OPERATION ................................. 35
CAN Communication System Description .............. 35
Schematic ............................................................... 36
Wiring Diagram — DTRL — ................................... 37
Terminals and Reference Values for BCM .............. 41
How to Proceed With Trouble Diagnosis ................ 42
Preliminary Check .................................................. 42
CHECK BCM CONFIGURATION ........................ 42
INSPECTION FOR POWER SUPPLY AND
GROUND CIRCUIT ............................................. 42
INSPECTION PARKING BRAKE SWITCH CIR-
CUIT .................................................................... 43
CONSULT-II Functions ........................................... 44
Daytime Light Control Does Not Operate Properly
(Normal Headlamps Operate Properly) .................. 44
Aiming Adjustment .................................................. 46
Bulb Replacement .................................................. 46
Removal and Installation ........................................ 46
Disassembly and Assembly .................................... 46
AUTO LIGHT SYSTEM ............................................. 47
Component Parts and Harness Connector Location ... 47
System Description ................................................. 48
OUTLINE ............................................................. 48