ENGINE CONTROL SYSTEM
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Revision: August 20072004 QX56
System ChartUBS00GZD
*1: This sensor is not used to control the engine system. This is used only for the on board diagnosis.
*2: This sensor is not used to control the engine system under normal conditions.
*3: This input signal is sent to the ECM through CAN communication line.
*4: This output signal is sent from the ECM through CAN communication line.Input (Sensor) ECM Function Output (Actuator)
Camshaft position sensor (PHASE)
Crankshaft position sensor (POS)
Mass air flow sensor
Engine coolant temperature sensor
A/F sensor 1
Throttle position sensor
Accelerator pedal position sensor
Park/neutral position (PNP) switch
Intake air temperature sensor
Power steering pressure sensor
Ignition switch
Battery voltage
Knock sensor
Refrigerant pressure sensor
Stop lamp switch
ASCD steering switch
ASCD brake switch
Fuel level sensor*1 *3
EVAP control system pressure sensor
Fuel tank temperature sensor*1
Heated oxygen sensor 2*2
TCM (Transmission control module)*3
ABS actuator and electric unit (control unit)*3
Air conditioner switch*3
Wheel sensor*3
Electrical load signal*3
Fuel injection & mixture ratio control Fuel injector
Electronic ignition system Power transistor
Nissan torque demand control system
Electric throttle control actuator
Fuel injector
Fuel pump control Fuel pump relay
ASCD vehicle speed control Electric throttle control actuator
On board diagnostic system
MIL (On the instrument panel)*
4
A/F sensor 1 heater control A/F sensor 1 heater
Heated oxygen sensor 2 heater control Heated oxygen sensor 2 heater
EVAP canister purge flow controlEVAP canister purge volume control
solenoid valve
Air conditioning cut control
Air conditioner relay*
4
Cooling fan control
Cooling fan relay*4
ON BOARD DIAGNOSIS for EVAP system EVAP canister vent control valve
BASIC SERVICE PROCEDURE
EC-45
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Revision: August 20072004 QX56
On vehicles equipped with daytime light systems, if the parking brake is applied before the engine
is started, the headlamp will not be illuminated.
Steering wheel: Neutral (Straight-ahead position)
Vehicle speed: Stopped
Transmission: Warmed-up
For models with CONSULT-II, drive vehicle until “FLUID TEMP SE” in “DATA MONITOR” mode of “A/T”
system indicates less than 0.9V.
For models without CONSULT-II, drive vehicle for 10 minutes.
OPERATION PROCEDURE
With CONSULT-II
1. Perform EC-44, "Accelerator Pedal Released Position Learning" .
2. Perform EC-44, "
Throttle Valve Closed Position Learning" .
3. Start engine and warm it up to normal operating temperature.
4. Check that all items listed under the topic PREPARATION (previously mentioned) are in good order.
5. Select “IDLE AIR VOL LEARN” in “WORK SUPPORT” mode.
6. Touch “START” and wait 20 seconds.
7. Make sure that “CMPLT” is displayed on CONSULT-II screen. If
“CMPLT” is not displayed, Idle Air Volume Learning will not be
carried out successfully. In this case, find the cause of the inci-
dent by referring to the Diagnostic Procedure below.
8. Rev up the engine two or three times and make sure that idle
speed and ignition timing are within the specifications.
Without CONSULT-II
NOTE:
It is better to count the time accurately with a clock.
It is impossible to switch the diagnostic mode when an accelerator pedal position sensor circuit
has a malfunction.
1. Perform EC-44, "
Accelerator Pedal Released Position Learning" .
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ITEM SPECIFICATION
Idle speed 650±50 rpm (in P or N position)
Ignition timing 15±5° BTDC (in P or N position)
MBIB0238E
TROUBLE DIAGNOSIS - SPECIFICATION VALUE
EC-123
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Revision: August 20072004 QX56
TROUBLE DIAGNOSIS - SPECIFICATION VALUEPFP:00031
DescriptionUBS00H09
The specification (SP) value indicates the tolerance of the value that is displayed in “DATA MONITOR (SPEC)”
mode of CONSULT-II during normal operation of the Engine Control System. When the value in “DATA MONI-
TOR (SPEC)” mode is within the SP value, the Engine Control System is confirmed OK. When the value in
“DATA MONITOR (SPEC)” mode is NOT within the SP value, the Engine Control System may have one or
more malfunctions.
The SP value is used to detect malfunctions that may affect the Engine Control System, but will not light the
MIL.
The SP value will be displayed for the following three items:
B/FUEL SCHDL (The fuel injection pulse width programmed into ECM prior to any learned on board cor-
rection)
A/F ALPHA-B1/B2 (The mean value of air-fuel ratio feedback correction factor per cycle)
MAS A/F SE-B1 (The signal voltage of the mass air flow sensor)
Testing ConditionUBS00H0A
Vehicle driven distance: More than 5,000 km (3,017 miles)
Barometric pressure: 98.3 - 104.3 kPa (1.003 - 1.064 kg/cm2 , 14.25 - 15.12 psi)
Atmospheric temperature: 20 - 30°C (68 - 86°F)
Engine coolant temperature: 75 - 95°C (167 - 203°F)
Transmission: Warmed-up*1
Electrical load: Not applied*2
Engine speed: Idle
*1: After the engine is warmed up to normal operating temperature, drive vehicle until “FLUID TEMP SE” (A/T
fluid temperature sensor signal) indicates more than 60°C (140°F).
*2: Rear window defogger switch, air conditioner switch, lighting switch are OFF. Steering wheel is straight
ahead.
Inspection ProcedureUBS00H0B
NOTE:
Perform “DATA MONITOR (SPEC)” mode in maximum scale display.
1. Perform EC-79, "
Basic Inspection" .
2. Confirm that the testing conditions indicated above are met.
3. Select “B/FUEL SCHDL”, “A/F ALPHA-B1”, “A/F ALPHA-B2”
and “MAS A/F SE-B1” in “DATA MONITOR (SPEC)” mode with
CONSULT-II.
4. Make sure that monitor items are within the SP value.
5. If NG, go to EC-124, "
Diagnostic Procedure" .
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EC-542Revision: August 2007
DTC P1574 ICC VEHICLE SPEED SENSOR
2004 QX56
DTC P1574 ICC VEHICLE SPEED SENSORPFP:31036
Component DescriptionUBS00HZ6
The ECM receives two vehicle speed signals via CAN communication line. One is sent from “unified meter and
A/C amp.”, and the other is from TCM (Transmission control module). The ECM uses these signals for ICC
control. Refer to ACS-6, "
DESCRIPTION" for ICC functions.
On Board Diagnosis LogicUBS00HZ7
This self-diagnosis has the one trip detection logic.
The MIL will not light up for this self-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 ProcedureUBS00HZ8
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.
2. Select “DATA MONITOR” mode with CONSULT-II.
3. Drive the vehicle at more than 40 km/h (25MPH).
4. If DTC is detected, go to EC-543, "
Diagnostic Procedure" .
WITH GST
Follow the procedure “WITH CONSULT-II” above.
DTC No. Trouble Diagnosis Name DTC Detecting Condition Possible Cause
P1574
1574ICC 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.)
Unified meter and A/C amp.
ABS actuator and electric unit (control unit)
Wheel sensor
TCM
ECM
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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
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TERMINOLOGY
GI-53
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Revision: August 20072004 QX56
***: Not applicableTransmission control module TCM A/T control unit
Turbocharger TC Turbocharger
Vehicle speed sensor VSS Vehicle speed sensor
Volume air flow sensor VAFS Air flow meter
Warm up oxidation catalyst WU-OC Catalyst
Warm up oxidation catalytic converter sys-
temWU-OC system ***
Warm up three way catalyst WU-TWC Catalyst
Warm up three way catalytic converter sys-
temWU-TWC system ***
Wide open throttle position switch WOTP switch Full switchNEW TERMNEW ACRONYM /
ABBREVIATIONOLD TERM
IDX-2
ALPHABETICAL INDEX
Numerics
2-4WD shift solenoid valve ................................ TF-95
4LO indicator lamp ............................................. TF-90
4WD shift indicator lamp .................................... TF-85
4WD shift switch ................................................ TF-95
4WD solenoid valve ........................................... TF-95
4WD warning lamp ............................................ TF-13
A
A/C air flow ...................................................... ATC-29
A/C compressor clutch removal and installation .. ATC-
167
A/C compressor mounting ............................. ATC-166
A/C compressor precaution ............................. ATC-11
A/C compressor special service tool ................ ATC-14
A/C control operation (auto A/C) ...................... ATC-26
A/C diagnostic work flow (auto A/C) .............. ATC-120
A/C evaporator ............................................... ATC-175
A/C HFC134a (R134a) system identification ..... ATC-7
A/C HFC134a (R134a) system precaution ........ ATC-5
A/C HFC134a (R134a) system service procedure ATC-
162
A/C HFC134a (R134a) system service tools ... ATC-14
A/C HFC134a system service equipment precaution ...
ATC-11
A/C lubricant (R134a) ...................................... ATC-22
A/C lubrication oil ............................................. ATC-22
A/C operational check ....................... ATC-56, ATC-59
A/C self-diagnoses (auto A/C) ........ ATC-53, ATC-120
A/C service data specification ........................ ATC-182
A/C trouble diagnoses (auto A/C) .................... ATC-33
A/C, A - Wiring diagram ................................... ATC-41
A/T - Wiring diagram .......................................... AT-52
A/T fluid checking ...................... AT-13, AT-58, MA-21
A/T fluid cooler cleaning .................................... AT-15
A/T fluid replacement ............................. AT-13, MA-23
A/T fluid temperature sensor ........................... AT-131
A/T IND - Wiring diagram .................................... DI-41
A/T indicator ........................................................ DI-41
A/T shift lock system ........................................ AT-236
A/T trouble diagnoses ........................................ AT-43
ABS - Wiring diagram ..................................... BRC-16
ABS (anti-lock brake system) ........................... BRC-7
Accelerator control system ............................... ACC-2
Accelerator pedal position (APP) sensor . EC-556, EC-
562, EC-576
Accelerator pedal released position learning ..... EC-44
AF1B1-Wiring diagram EC-431, EC-439, EC-447, EC-
456, EC-466, EC-475, EC-487
AF1B2-Wiring diagram EC-433, EC-441, EC-449, EC-
458, EC-468, EC-477, EC-489
AF1HB1-Wiring diagram .................................. EC-355
AF1HB2-Wiring diagram .................................. EC-357
Aiming adjustment .................................. LT-31, LT-78
Air bag .............................................................. SRS-3
Air cleaner and air duct ..................................... EM-14
Air cleaner filter replacement ............................ MA-15
Air conditioner cut control ................................. EC-30
Air flow meter - See Mass air flow sensor EC-146, EC-
154
Air fuel ratio sensor 1 .. EC-429, EC-437, EC-445, EC-
454, EC-463, EC-472, EC-484
Air fuel ratio sensor 1 heater ........................... EC-354
Air mix. door motor .......................................... ATC-67
All - mode 4WD system ..................................... TF-10
Ambient sensor ............................. ATC-125, ATC-136
Angular tightening application ............................. EM-3
APPS1 - Wiring diagram ................................. EC-558
APPS2 - Wiring diagram ................................. EC-564
APPS3 - Wiring diagram ................................. EC-578
ASC/BS - Wiring diagram ............................... EC-536
ASC/SW - Wiring diagram .............................. EC-519
ASCBOF - Wiring diagram .............................. EC-622
ASCD .............................................................. EC-647
ASCD (automatic speed control device) ........... ACS-3
ASCD brake switch ........................... EC-534, EC-621
ASCD indicator lamp ....................................... EC-628
ASCD steering switch ..................................... EC-517
ASCIND - Wiring diagram ............................... EC-629
ATP switch ......................................................... TF-96
ATP warning lamp .............................................. TF-89
AUDIO - Wiring diagram .................................... AV-10
AUT/DP - Wiring diagram .................................. SE-19
Auto air conditioner - Wiring diagram .............. ATC-41
Auto anti-dazzling inside mirror ........... GW-76, GW-77
Autolamp ............................................................ LT-47
Automatic amplifier ......................................... ATC-60
Automatic transmission number .......................... GI-48
AV and NAVI control unit ................................... AV-63
AV communication line ...................................... AV-87
B
Back door trim ..................................................... EI-31
Back sonar .......................................................... DI-59
BACK/L - Wiring diagram ................................. LT-106
Back-up lamp ................................................... LT-106
Ball joint (front) ................................................ FSU-15
Basic inspection ................................................ EC-79
Battery ................................................................. SC-4
Battery/Starting/Charging System Tester SC-6, SC-12,
SC-19
BCM (Body control module) .............................. BCS-3
Block heater ...................................................... EM-73
Blower motor ................................... ATC-83, ATC-140
Body alignment ................................................ BL-174
Body component parts ..................................... BL-161
Body construction ............................................ BL-173
Body exterior paint color .................................. BL-160
Body mounting ................................................. BL-159
Body repair ....................................................... BL-160
Body sealing .................................................... BL-170
Brake booster .................................................... BR-17
Brake fluid level ................................................. MA-27
Brake hydraulic line ........................................... BR-12
Brake inspection ............................................... MA-28
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
V
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
W
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