2004 INFINITI QX56 Vdc

EC-340Revision: August 2007
DTC P0500 VSS
2004 QX56
DTC P0500 VSSPFP:32702
DescriptionUBS00H6C
NOTE:
If DTC P0500 is displayed with DTC U1000 or U1001, first perform the trouble diagnosis for DTC U1000,
U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .
The vehicle speed signal is sent to the combination meter from the “ABS actuator and electric unit (control
unit)” by CAN communication line. The c combination meter then sends a signal to the ECM by CAN commu-
nication line.
On Board Diagnosis LogicUBS00H6D
DTC Confirmation ProcedureUBS00H6E
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Steps 1 and 2 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Read “VHCL SPEED SE” in “DATA MONITOR” mode with CONSULT-II. The vehicle speed on CONSULT-
II should exceed 10 km/h (6 MPH) when rotating wheels with suitable gear position.
If NG, go to EC-341, "
Diagnostic Procedure" .
If OK, go to following step.
3. Select “DATA MONITOR” mode with CONSULT-II.
4. Warm engine up to normal operating temperature.
5. Maintain the following conditions for at least 60 consecutive sec-
onds.
6. If 1st trip DTC is detected, go to EC-341, "
Diagnostic Procedure"
.
Overall Function CheckUBS00H6F
Use this procedure to check the overall function of the vehicle speed sensor circuit. During this check, a 1st
trip DTC might not be confirmed.
WITH GST
1. Lift up drive wheels.
DTC No. Trouble diagnosis name DTC detecting condition Possible cause
P0500
0500Vehicle speed sensorThe almost 0 km/h (0 MPH) signal from
vehicle speed sensor is sent to ECM
even when vehicle is being driven.

Harness or connectors
(The CAN communication line is open or
shorted)

Harness or connectors
(The vehicle speed signal circuit is open or
shorted)

Wheel sensor

Combination meter

ABS actuator and electric unit (control unit)
ENG SPEED More than 1,600 rpm
COOLAN TEMP/S More than 70°C (158°F)
B/FUEL SCHDL More than 6.9 msec
Selector lever Except P or N position
PW/ST SIGNAL OFF
SEF 1 96 Y

DTC P1572 ASCD BRAKE SWITCH
EC-535
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Revision: August 20072004 QX56
DTC Confirmation ProcedureUBS00HBI
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Steps 3 and 4 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a
road test is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Drive the vehicle for at least 5 consecutive seconds under the following conditions.
If DTC is detected, go to EC-537, "
Diagnostic Procedure" .
If DTC is not detected, go to the following step.
4. Drive the vehicle for at least 5 consecutive seconds under the following conditions.
5. If DTC is detected, go to EC-537, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
VHCL SPEED SE More than 30 km/h (19 MPH)
Selector lever Suitable position
Driving locationDepress the brake pedal for more than
five seconds so as not to come off from
the above-mentioned condition.

EC-544Revision: August 2007
DTC P1574 ASCD VEHICLE SPEED SENSOR
2004 QX56
DTC P1574 ASCD VEHICLE SPEED SENSORPFP:31036
Component DescriptionUBS00HBM
The ECM receives two vehicle speed sensor signals via CAN communication line. One is sent from combina-
tion meter and the other is from TCM (Transmission control module). The ECM uses these signals for ASCD
control. Refer to EC-647, "
AUTOMATIC SPEED CONTROL DEVICE (ASCD)" for ASCD functions.
On Board Diagnosis LogicUBS00HBN
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this diagnosis.
NOTE:

If DTC P1574 is displayed with DTC U1000, U1001, first perform the trouble diagnosis for DTC
U1000, U1001. Refer to EC-135, "
DTC U1000, U1001 CAN COMMUNICATION LINE" .

If DTC P1574 is displayed with DTC P0500, first perform the trouble diagnosis for DTC P0500.
Refer to EC-340, "
DTC P0500 VSS".

If DTC P1574 is displayed with DTC P0605, first perform the trouble diagnosis for DTC P0605.
Refer to EC-351, "
DTC P0605 ECM".
DTC Confirmation ProcedureUBS00HBO
CAUTION:
Always drive vehicle at a safe speed.
NOTE:
If DTC Confirmation Procedure has been previously conducted, always turn ignition switch OFF and wait at
least 10 seconds before conducting the next test.
TESTING CONDITION:
Step 3 may be conducted with the drive wheels lifted in the shop or by driving the vehicle. If a road test
is expected to be easier, it is unnecessary to lift the vehicle.
WITH CONSULT-II
1. Start engine (VDC switch OFF).
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Drive the vehicle at more than 40 km/h (25 MPH).
4. If DTC is detected, go to EC-545, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No.Trouble Diagnosis
NameDTC Detecting Condition Possible Cause
P1574
1574ASCD vehicle speed
sensorECM detects a difference between two vehicle
speed signals is out of the specified range.

Harness or connectors
(The CAN communication line is open or
shorted.)

Combination meter

ABS actuator and electric unit (control unit)

Wheel sensor

TCM

ECM
SEF 0 58 Y

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

IDX-8
ALPHABETICAL INDEX
Torque convertor clutch solenoid valve ... AT-118, AT-
121
Tow truck towing ................................................. GI-42
Towing point ....................................................... GI-43
TPS1 - Wiring diagram .................................... EC-238
TPS2 - Wiring diagram .................................... EC-173
TPS3 - Wiring diagram .................................... EC-571
Traction control system - Wiring diagram ....... BRC-16
Transfer control device .................................... TF-104
Transfer control unit inspection table ................. TF-55
Transfer dropping resistor .................................. TF-96
Transfer fluid temperature sensor ...................... TF-95
Transfer motor ................................................. TF-106
Transfer motor relay .......................................... TF-97
Transfer oil replacement ................................... MA-24
Transfer serial number ........................................ GI-48
Transmission serial number ................................ GI-48
Tread-FR&RR (Dimensions) ............................... GI-49
Trim ..................................................................... EI-34
TRNSCV - Wiring diagram ............................... BL-157
Trouble diagnoses .............................................. GI-11
Turbine revolution sensor ................................ AT-134
TURN - Wiring diagram ...................................... LT-83
Turn signal lamp ................................................. LT-80
Two trip detection logic ...................................... EC-49
Two-pole lift ........................................................ GI-41
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Vacuum hose (brake system) ............................ BR-20
Vacuum hose drawing (Engine control) ............. EC-24
Valve clearance ................................................ EM-52
Valve guide ....................................................... EM-66
Vanity mirror lamp ............................................. LT-129
VDC (vehicle dynamics control) ........................ BRC-7
VDC -Wiring diagram ...................................... BRC-16
Vehicle identification number .............................. GI-47
Vehicle recovery (freeing a stuck vehicle) .......... GI-43
Vehicle speed sensor (VSS) ............................ EC-340
VEHSEC - Wiring diagram ................................. BL-80
VENT/V - Wiring diagram .................. EC-294, EC-506
Video Monitor ..................................................... AV-60
Viscosity number (SAE) .................................... MA-11
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W/ANT - Wiring diagram .................................... AV-49
Wait detection switch ......................................... TF-96
WARN - Wiring diagram ..................................... DI-32
Warning chime .................................................... DI-43
Warning lamps .................................................... DI-31
Washer, front ..................................................... WW-4
Washer, rear .................................................... WW-33
Water pump ...................................................... CO-15
Water temperature gauge ..................................... DI-5
Wheel alignment (front) ..................................... FSU-6
Wheel alignment (rear) ................................... RSU-27
Wheel balance .................................................. MA-25
Wheel bearing (front) ......................................... FAX-5
Wheel bearing (rear) ......................................... RAX-5
Wheel hub (rear) ............................................... RAX-5
Wheel size .......................................................... GI-49
Wheelbase (Dimensions) .................................... GI-49
Width (Dimensions) ............................................. GI-49
WINDOW - Wiring diagram .............................. GW-22
Window, door ...................................... GW-69, GW-72
Windshield ....................................................... GW-11
WIP/R - Wiring diagram ................................... WW-37
WIPER - Wiring diagram .................................... WW-9
Wiper, front ........................................................ WW-4
Wiper, rear ....................................................... WW-33
Wiring Diagram (Cell code) list ......................... PG-61
Wiring diagram (Transfer) .................................. TF-18
Wiring diagrams .................................................. GI-15
WT-T/WARN - Wiring diagram .......................... WT-10

CAN COMMUNICATION
LAN-5
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Revision: August 20072004 QX56
CAN COMMUNICATIONPFP:23710
System DescriptionUKS000NU
CAN (Controller Area Network) is a serial communication line for real time application. It is an on-vehicle mul-
tiplex communication line with high data communication speed and excellent error detection ability. Many elec-
tronic control units are equipped onto a vehicle, and each control unit shares information and links with other
control units during operation (not independent). In CAN communication, control units are connected with 2
communication lines (CAN H line, CAN L line) allowing a high rate of information transmission with less wiring.
Each control unit transmits/receives data but selectively reads required data only.
CAN Communication UnitUKS000NV
Go to CAN system, when selecting your CAN system type from the following table.
×: Applicable
TYPE1
System diagram

Ty p e 1
Input/output signal chart
T: Transmit R: Receive Body typeWagon
Axle 2WD 4WD
EngineVK56DE
TransmissionA/T
Brake controlVDC
ICC system××
CAN system type 1234
CAN system trouble diagnosisLAN-16
LAN-50LAN-90LAN-126
PKIA8173E
Signals 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
Engine speed signal T R R R R
Engine status signal T R R

CAN COMMUNICATION
LAN-7
[CAN]
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LAN
Revision: August 20072004 QX56
Malfunction indicator lamp 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 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 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
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
unitBCMStee r-
ing
angle
sensorFront
air
control ABS
actua-
tor and
elec-
tric unit
(con-
trol
unit)IPDM
E/R