2001 INFINITI QX4 Vacuum cut

16 CHECK EVAP CANISTER VENT CONTROL VALVE-III
1. Clean the air passage (PortionAtoB) of EVAP canister vent control valve using an air blower.
2. Perform the Test No. 15 again.
OK or NG
OK©GO TO 17.
NG©Replace EVAP canister vent control valve.
17 CHECK INTERMITTENT INCIDENT
Refer to ªTROUBLE DIAGNOSIS FOR INTERMITTENT INCIDENTº, EC-140.
©INSPECTION END
DTC P1491 VACUUM CUT VALVE BYPASS VALVE
Diagnostic Procedure (Cont'd)
EC-602

SEF018Z
COMPONENT DESCRIPTIONNBEC0596S02Power ValveNBEC0596S0201The power valve is installed in intake manifold collector and used
to control the suction passage of the variable induction air control
system. It is set in the fully closed or fully opened position by the
power valve actuator operated by the vacuum stored in the surge
tank. The vacuum in the surge tank is controlled by the VIAS con-
trol solenoid valve.
SEF019Z
VIAS Control Solenoid ValveNBEC0596S0202The VIAS control solenoid valve cuts the intake manifold vacuum
signal for power valve control. It responds to ON/OFF signals from
the ECM. When the solenoid is off, the vacuum signal from the
intake manifold is cut. When the ECM sends an ON signal the coil
pulls the plunger downward and feeds the vacuum signal to the
power valve actuator.
ECM Terminals and Reference ValueNBEC0684Specification 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.
TERMI-
NAL
NO.WIRE
COLORITEM CONDITION DATA (DC Voltage)
16 Y/GVIAS control solenoid
valve[Engine is running]
IIdle speedBATTERY VOLTAGE
(11 - 14V)
[Engine is running]
IEngine speed is above 5,000 rpm.0 - 1.0V
GI
MA
EM
LC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
VARIABLE INDUCTION AIR CONTROL SYSTEM (VIAS)
Description (Cont'd)
EC-611

NBEL0145
Use the chart below to find out what each wiring
diagram code stands for.
Refer to the wiring diagram code in the alphabetical
index to find the location (page number) of each
wiring diagram.
Code Section Wiring Diagram Name
1STSIG AT A/T 1ST Signal
2NDSIG AT A/T 2ND Signal
3RDSIG AT A/T 3RD Signal
4THSIG AT A/T 4TH Signal
A/C, A HA Auto Air Conditioner
AAC/V EC IACV-AAC Valve
ABS BR Anti-lock Brake System
AP/SEN EC Absolute Pressure Sensor
ASCD EL Automatic Speed Control Device
AT/C EC A/T Control
ATDIAG EC A/T Diagnosis Communication
Line
AT/IND EL A/T Indicator Lamp
AUDIO EL Audio
AUT/DP EL Automatic Drive Positioner
BA/FTS AT A/T Fluid Temperature Sensor
and TCM Power Supply
BACK/L EL Back-up Lamp
BYPS/V EC Vacuum Cut Valve Bypass Valve
CHARGE SC Charging System
CHIME EL Warning Chime
CIGAR EL Cigarette Lighter
CLOCK EL Clock
COMPAS EL Compass and Thermometer
D/LOCK EL Power Door Lock
DEF EL Rear Window Defogger
DTRL EL Headlamp Ð With Daytime Light
System Ð
ECTS EC Engine Coolant Temperature Sen-
sor
ENGSS AT Engine Speed Signal
F/FOG EL Front Fog Lamp
F/LID EL Fuel Lid Opener
F/PUMP EC Fuel Pump Control
FICD EC IACV-FICD Solenoid Valve
FLS1 EC Fuel Gauge
Code Section Wiring Diagram Name
FLS2 EC Fuel Gauge
FLS3 EC Fuel Gauge
FTS AT A/T Fluid Temperature Sensor
FUELLH EC Fuel Injection System Function
(Left Bank)
FUELRH EC Fuel Injection System Function
(Right Bank)
H/AIM EL Headlamp Aiming Control System
H/LAMP EL Headlamp
HORN EL Horn
HSEAT EL Heated Seat
IATS EC Intake Air Temperature Sensor
IGN/SG EC Ignition Signal
ILL EL Illumination
INJECT EC Injector
INT/L EL Interior, Spot, Vanity Mirror, and
Luggage Room Lamps
IVC-L EC Intake Valve Timing Control Sole-
noid Valve LH
IVC-R EC Intake Valve Timing Control Sole-
noid Valve RH
IVCS EL INFINITI Communicator
IVCS-L EC Intake Valve Timing Control Posi-
tion Sensor LH
IVCS-R EC Intake Valve Timing Control Posi-
tion Sensor RH
KS EC Knock Sensor
LAN AT A/T Communication Line
LOAD EC Electrical Load Signal
LPSV AT Line Pressure Solenoid Valve
MAFS EC Mass Air Flow Sensor
MAIN AT Main Power Supply and Ground
Circuit
MAIN EC Main Power Supply and Ground
Circuit
METER EL Speedometer, Tachometer, Temp.,
Oil, and Fuel Gauges
MIL/DL EC MIL and Data Link Connectors
MIRROR EL Door Mirror
MULTI EL Multi-remote Control System
NATS EL IVIS (Infiniti Vehicle Immobiliser
System)
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
WIRING DIAGRAM CODES (CELL CODES)
EL-457

E
ECM input/output signal ...............................EC-127
ECTS - Wiring diagram ........................EC-171, 189
Electric sun roof ............................................EL-173
Electrical diagnoses.........................................GI-24
Electrical ignition system ................................EC-30
Electrical unit ................................................Foldout
Electrical units location .................................EL-436
Engine compartment .......................................BT-58
Engine control circuit diagram........................EC-24
Engine control component parts
location .......................................................EC-20
Engine control module (ECM) ......................EC-444
Engine control system diagram and
chart ............................................................EC-25
Engine coolant temperature sensor
(ECTS) ..............................................EC-169, 187
Engine fail-safe system ................................EC-117
Engine oil filter replacement ..........................MA-18
Engine oil precautions .......................................GI-8
Engine oil replacement ..................................MA-18
Engine outer component parts ......................EM-10
Engine removal ..............................................EM-57
Engine room - See Engine
compartment................................................BT-58
Engine serial number ......................................GI-43
EVAP canister.................................................EC-33
EVAP canister purge volume control
solenoid valve.............................EC-32, 367, 541
EVAP canister vent control
valve .........................................EC-374, 553, 573
EVAP control system (small leak)
diagnosis ..................................EC-352, 394, 526
EVAP control system pressure sensor.........EC-381
EVAP control system purge flow moni-
toring diagnosis.........................................EC-561
EVAP vapor lines inspection ..........................MA-20
Evaporative emission (EVAP) system ............EC-32
Exhaust system ................................................FE-8
Exhaust system inspection ............................MA-21
Exterior ............................................................BT-35
F
4LO indicator lamp........................................TF-104
4WD shift indicator lamp.................................TF-98
4WD shift switch ............................................TF-111
4WD solenoid valve.......................................TF-111
4WD warning lamp .........................................TF-13
Fan control amp. ............................................HA-98
F/FOG - Wiring diagram .................................EL-72
Final drive disassembly ..................................PD-43
Final drive pre-inspection ...............................PD-43
Final drive removal and installation ...............PD-43
Finisher, interior - See Trim ............................BT-28
F/LID - Wiring diagram .................................EL-180
Fluid temperature sensor (A/T) .....................AT-110Fluids ..............................................................MA-11
Flywheel runout..............................................EM-70
FO2H-L - Wiring diagram .............................EC-243
FO2H-R - Wiring diagram ............................EC-242
Fog lamp, front................................................EL-70
Fog lamp, front, removal and
installation ...................................................BT-12
Forward clutch ...............................................AT-320
F/PUMP - Wiring diagram ............................EC-627
Freeze frame data ..........................................EC-60
FRO2LH - Wiring diagram ...........EC-197, 223, 235
FRO2RH - Wiring diagram...........EC-196, 222, 234
Front axle..........................................................AX-2
Front bumper ..................................................BT-12
Front case (Transfer) ....................................TF-133
Front combination lamp removal and
installation ...................................................BT-12
Front disc brake .............................................BR-22
Front door .......................................................BT-18
Front drive shaft (Transfer) ...........................TF-125
Front final drive disassembly (4WD) ..............PD-18
Front final drive pre-inspection (4WD) ...........PD-18
Front final drive removal and installa-
tion (4WD)...................................................PD-18
Front fog lamp.................................................EL-70
Front fog lamp removal and installation .........BT-12
Front heated oxygen sensor (HO2S)
(Left bank) ................EC-192, 202, 210, 218, 231
Front heated oxygen sensor (HO2S)
(Right bank) .............EC-192, 202, 210, 218, 231
Front heated oxygen sensor heater
(Left bank).................................................EC-240
Front heated oxygen sensor heater
(Right bank) ..............................................EC-240
Front revolution sensor (Transfer) ................TF-112
Front seat ........................................................BT-41
Front seat belt ..................................................RS-4
Front suspension ..............................................SU-2
Front washer .................................................EL-136
Front wiper ....................................................EL-136
Fuel cut control (at no load & high
engine speed) .............................................EC-32
Fuel filler lid.....................................................BT-15
Fuel filter replacement ...................................MA-16
Fuel gauge ......................................................EL-94
Fuel injection system (Left bank) .........EC-294, 302
Fuel injection system (Right bank) ......EC-294, 302
Fuel lid opener, electric.................................EL-180
Fuel line inspection ........................................MA-16
Fuel precautions ................................................GI-8
Fuel pressure check .......................................EC-39
Fuel pressure regulator ..................................EC-40
Fuel pressure release ....................................EC-39
Fuel pump ....................................................EC-625
Fuel system ......................................................FE-4
Fuel tank temperature sensor ......................EC-309
Fuel tank vacuum relief valve ........................EC-33
FUELLH - Wiring diagram....................EC-297, 305
FUELRH - Wiring diagram ...................EC-296, 304
Fuse ................................................................EL-16
Fuse block ....................................................Foldout
ALPHABETICAL INDEX
IDX-4

S/VCSW - Wiring diagram ...........................EC-493
Swirl control valve control solenoid
valve .........................................................EC-458
Swirl control valve control vacuum
check switch .............................................EC-493
SWL/V - Wiring diagram ..............................EC-458
Symbols and abbreviations .............................GI-10
Symptom matrix chart...................................EC-118
System readiness test (SRT) code ................EC-61
T
2-4WD shift solenoid valve............................TF-111
Tachometer .....................................................EL-94
Tail lamp ..........................................................EL-61
TAIL/L - Wiring diagram ..................................EL-63
TCM circuit diagram ........................................AT-13
TCM inspection table ......................................AT-92
TFTS - Wiring diagram .................................EC-311
THEFT - Wiring diagram ...............................EL-300
Theft warning system....................................EL-294
Thermometer .................................................EL-110
Thermostat ......................................................LC-16
Three way catalyst function (Left bank) .......EC-347
Three way catalyst function (Right
bank) .........................................................EC-347
Three way catalyst precautions.........................GI-6
Throttle bodies ...............................................EM-12
Throttle position sensor (TPS) .....................EC-174
Throttle position sensor adjustment .............EC-101
Throttle position switch ...........EC-431, AT-184, 264
Tie-rod .............................................................ST-21
Tie-rod ball joints.............................................ST-21
Tightening torque of standard bolts.................GI-50
Timing chain ...................................................EM-20
Tire rotation ....................................................MA-24
Tire size ...........................................................GI-44
TLID - Wiring diagram ..................................EL-179
Tooth contact (front final drive 4WD) .............PD-29
Tooth contact diff. ...........................................PD-56
Torque converter installation .........................AT-278
Torque convertor clutch solenoid
valve ..................................................AT-152, 161
Tow truck towing ..............................................GI-47
Towing point.....................................................GI-49
TP/SW - Wiring diagram ..............................EC-434
TPS - Wiring diagram...................................EC-180
Transfer control unit inspection table..............TF-55
Transfer dropping resistor .............................TF-112
Transfer fluid replacement (Part time
4WD model) ...............................................MA-22
Transfer fluid temperature sensor .................TF-111
Transfer motor ...............................................TF-117
Transfer motor relay ......................................TF-113
Transfer serial number ....................................GI-43
TRANSMT - Wiring diagram .........................EL-325
Tread-FR&RR (Dimensions)............................GI-43
Trim .................................................................BT-28
Trouble diagnoses ...........................................GI-34
Trunk lid opener, electric...............................EL-178Turbine revolution sensor..............................AT-202
TURN - Wiring diagram ..................................EL-77
Turn signal lamp .............................................EL-75
Two trip detection logic ..................................EC-59
Two-pole lift .....................................................GI-47
U
Under body .....................................................BT-60
V
Vacuum cut valve ...........................................EC-32
Vacuum cut valve bypass valve.....EC-32, 585, 591
Vacuum hose (brake system).........................BR-21
Vacuum hose drawing (Engine control) .........EC-26
Valve clearance ..............................................EM-52
Valve guide.....................................................EM-43
Valve seat.......................................................EM-45
Valve spring....................................................EM-46
Vehicle identification number...........................GI-42
Vehicle recovery (freeing a stuck
vehicle) .........................................................GI-49
Vehicle speed sensor (VSS) ........................EC-417
VENT/V - Wiring diagram ............EC-376, 555, 576
Ventilation air filter ........................................HA-159
VIAS .............................................................EC-610
VIAS - Wiring diagram .................................EC-610
Viscosity number (SAE) .................................MA-12
VSS - Wiring diagram ..................................EC-420
W
Wait detection switch ....................................TF-112
WARN - Wiring diagram................................EL-115
Warning chime ..............................................EL-125
Warning lamps ..............................................EL-114
Washer, front .................................................EL-136
Washer, rear..................................................EL-141
Water pump ....................................................LC-12
Water temperature gauge ...............................EL-94
Weatherstrip - See Exterior ............................BT-35
Wheel balance ...............................................MA-24
Wheel bearing (front)........................................AX-4
Wheel bearing (rear) ......................................AX-18
Wheel hub (front)..............................................AX-6
Wheel sensors (ABS)...............................BR-56, 80
Wheel size .......................................................GI-44
Wheelarch height .............................................SU-5
Wheelbase (Dimensions) ................................GI-43
Wide open & closed throttle position
switch ........................................................EC-174
Width (Dimensions) .........................................GI-43
WINDOW - Wiring diagram ..........................EL-245
Window, door ..................................................BT-18
Window, rear side ...........................................BT-55
Window, side - See Rear side window ...........BT-55
ALPHABETICAL INDEX
IDX-8