2001 INFINITI QX4 brake sensor

SEL255W
Fail-safe SystemNBEL0217DESCRIPTIONNBEL0217S01When the fail-safe system senses a malfunction, it deactivates
ASCD operation. The SET indicator in the combination meter will
then flash.
MALFUNCTION DETECTION CONDITIONSNBEL0217S02
Detection conditionsASCD operation during malfunc-
tion detection
IASCD steering (RESUME/ACCEL, CANCEL, SET/COAST) switch is stuck.
IVacuum motor ground circuit or power circuit is open or shorted.
IAir valve ground circuit or power circuit is open or shorted.
IRelease valve ground circuit or power circuit is open or shorted.
IVehicle speed sensor is faulty.
IASCD control unit internal circuit is malfunctioning.IASCD is deactivated.
IVehicle speed memory is can-
celed.
IASCD brake switch or stop lamp switch is faulty.IASCD is deactivated.
IVehicle speed memory is not
canceled.
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Fail-safe System
EL-229

Trouble DiagnosesNBEL0218SYMPTOM CHARTNBEL0218S01
PROCEDURE Diagnostic procedure
REFERENCE PAGE (EL- ) 231 232 233 234 235 235 237
SYMPTOM
FAIL-SAFE SYSTEM CHECK
POWER SUPPLY AND GROUND CIRCUIT CHECK
ASCD BRAKE/STOP LAMP SWITCH CHECK
ASCD STEERING SWITCH CHECK
VEHICLE SPEED SENSOR CHECK
ASCD PUMP CIRCUIT CHECK
ASCD ACTUATOR/PUMP CHECK
ASCD cannot be set. (ªCRUISEº indica-
tor lamp does not ON.)XXH3
ASCD cannot be set. (ªSETº indicator
lamp does not blink.)XXX
ASCD cannot be set. (ªSETº indicator
lamp blinks.H1)X XXXX
Vehicle speed does not decrease after
SET/COAST switch has been pressed.XX
Vehicle speed does not return to the set
speed after RESUME/ACCEL switch has
been pressed.H2XX
Vehicle speed does not increase after
RESUME/ACCEL switch has been
pressed.XX
System is not released after CANCEL
switch (steering) has been pressed.XX
Large difference between set speed and
actual vehicle speed.XXX
Deceleration is greatest immediately
after ASCD has been set.XXX
H1: It indicates that system is in fail-safe. After completing diagnostic procedures, perform ªFAIL-SAFE SYSTEM CHECKº (EL-231) to
verify repairs.
H2: If vehicle speed is greater than 40 km/h (25 MPH) after system has been released, pressing RESUME/ACCEL switch returns vehicle
speed to the set speed previously achieved. However, doing so when the ASCD main switch is turned to ªOFFº, vehicle speed will not
return to the set speed since the memory is canceled.
H3: Check only main switch built-in steering switch.
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses
EL-230

SEL417V
FAIL-SAFE SYSTEM CHECK=NBEL0218S021. Turn ignition switch to ON position.
2. Turn ASCD main switch to ON and check if the SET indicator
blinks.
If the indicator lamp blinks, check the following.
IASCD steering switch. Refer to EL-234.
SEL767P
3. Drive the vehicle at more than 40 km/h (25 MPH) and push
SET/COAST switch.
If the indicator lamp blinks, check the following.
IVehicle speed sensor. Refer to EL-235.
IASCD pump circuit. Refer to EL-235.
IReplace control unit.
SAT797A
4. Depress brake pedal slowly (brake pedal should be depressed
more than 5 seconds).
If the indicator lamp blinks, check the following.
IASCD brake/stop lamp switch. Refer to EL-233.
5. END. (System is OK.)
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses (Cont'd)
EL-231

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)
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WIRING DIAGRAM CODES (CELL CODES)
EL-457

Removal and InstallationNBEM0042WARNING:
ISituate vehicle on a flat and solid surface.
IPlace chocks at front and back of rear wheels.
IDo not remove engine until exhaust system has com-
pletely cooled off. Otherwise, you may burn yourself
and/or fire may break out in fuel line.
IFor safety during subsequent steps, the tension of wires
should be slackened against the engine.
IBefore disconnecting fuel hose, release fuel pressure
from fuel line.
Refer to EC-39, ªFuel Pressure Releaseº.
IBefore removing front axle from transmission, place
safety stands under designated front supporting points.
Refer to GI section for lifting points and towing.
IBe sure to hoist engine and transmission in a safe man-
ner.
IFor engines not equipped with engine slingers, attach
proper slingers and bolts described in PARTS CATALOG.
CAUTION:
IWhen lifting engine, be careful not to strike adjacent parts,
especially accelerator wire casing, brake lines, and brake
master cylinder.
IIn hoisting the engine, always use engine slingers in a
safe manner.
IBefore separating engine and transmission, remove
crankshaft position sensor (POS) from the assembly.
IAlways take extra care not to damage edge of crankshaft
position sensor (POS), or ring gear teeth.GI
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ENGINE ASSEMBLY
Removal and Installation
EM-57

A
AAC/V - Wiring diagram ...............................EC-425
ABS - Wiring diagram ....................................BR-37
ABS sensor rotor ........................................AX-6, 19
Absolute pressure sensor ............................EC-158
A/C air flow .....................................................HA-25
A/C component layout ....................................HA-19
A/C compressor clutch removal and
installation .................................................HA-150
A/C compressor precaution..............................HA-6
A/C compressor special service tool..............HA-10
A/C control operation (auto A/C) ....................HA-23
A/C diagnostic work flow (auto A/C) ..............HA-65
A/C HFC134a (R134a) system
precaution .....................................................HA-2
A/C HFC134a (R134a) system service
procedure ..................................................HA-144
A/C HFC134a (R134a) system service
tools.............................................................HA-11
A/C HFC134a system service equip-
ment precaution ............................................HA-7
A/C lubricant (R134a)...................................HA-146
A/C operational check ....................................HA-66
A/C performance chart .................................HA-116
A/C performance test diagnoses ..................HA-114
A/C relay .......................................................HA-110
A/C self-diagnoses (auto A/C)........................HA-44
A/C service data specification ......................HA-160
A/C system description (auto A/C) .................HA-23
A/C trouble diagnoses (auto A/C) ..................HA-27
A/C, A - Wiring diagram ...........................HA-31, 36
Accelerator control system ...............................FE-3
Accelerator wire adjustment .............................FE-3
Actuator lever (Transfer) ...............................TF-120
Air bag ............................................................RS-10
Air bag disposal..............................................RS-22
Air bag precautions ...........................................GI-3
Air bleeding for brake system ..........................BR-8
Air cleaner filter replacement .........................MA-17
Air conditioner cut control ..............................EC-31
Air flow meter - See Mass air flow
sensor .......................................................EC-150
Air mix door control linkage adjustment.........HA-85
Air mix. door motor ................................HA-82, 141
Air spoiler, rear................................................BT-35
All - mode 4WD system ..................................TF-10
Alternator ........................................................SC-28
Ambient sensor ............................................HA-129
Angular tightening application..........................EM-3
Antenna - See Power antenna .....................EL-169
Anti-lock brake system - Wiring
diagram .......................................................BR-37
AP/SEN - Wiring diagram ............................EC-160
ASCD (automatic speed control device) ......EL-221
ASCD - Wiring diagram ................................EL-225
A/T - Wiring diagram - AT - FTS ...................AT-107
A/T - Wiring diagram - AT - MAIN ...................AT-96
A/T - Wiring diagram - AT - PNP/SW............AT-101A/T - Wiring diagram - AT - VSS A/T ............AT-113
A/T control ....................................................EC-440
A/T diagnosis communication line................EC-603
A/T fluid temperature sensor .........................AT-110
A/T self-diagnoses...........................................AT-46
A/T shift lock system .....................................AT-265
A/T shift lock system - Wiring diagram .........AT-266
A/T trouble diagnoses .....................................AT-53
A/T Wiring diagram - AT - ENG SS...............AT-117
A/T Wiring diagram AT - 1ST ........................AT-123
A/T Wiring diagram AT - 2ND .......................AT-129
A/T Wiring diagram AT - 3RD .......................AT-135
A/T Wiring diagram AT - 4TH ........................AT-142
A/T Wiring diagram AT - BA/FTS ..................AT-192
A/T Wiring diagram AT - LPSV .....................AT-164
A/T Wiring diagram AT - NONDTC ...............AT-215
A/T Wiring diagram AT - OVRCSV ...............AT-187
A/T Wiring diagram AT - SSV/A ....................AT-169
A/T Wiring diagram AT - SSV/B ....................AT-173
A/T Wiring diagram AT - TCCSIG .................AT-156
A/T Wiring diagram AT - TCV .......................AT-150
A/T Wiring diagram AT - TPS........................AT-179
A/T Wiring diagram AT - VSSMTR................AT-199
AT/C - Wiring diagram ..................................EC-442
ATP switch.....................................................TF-112
ATP warning lamp .........................................TF-102
Audio .............................................................EL-160
AUDIO - Wiring diagram ...............................EL-162
Audio and A/C control removal and
installation - See Instrument panel .............BT-21
AUT/DP - Wiring diagram .............................EL-191
Auto air conditioner - Wiring diagram ......HA-31, 36
Automatic amplifier...................................HA-40, 72
Automatic drive positioner ............................EL-186
Automatic speed control system - See
ASCD ........................................................EL-221
Automatic transmission fluid
replacement ................................................MA-21
Automatic transmission number ......................GI-43
Auxiliary air control (AAC) valve ..................EC-422
Axle housing (rear) .........................................AX-19
B
Back door ........................................................BT-15
Back door opener - See Back door ................BT-15
Back door trim.................................................BT-34
Back-up lamp ..................................................EL-69
BACK/L - Wiring diagram................................EL-69
Ball joint (front) ...............................................SU-12
Base idle air volume initialiging......................EC-57
Basic inspection ...........................................EC-101
Battery ..............................................................SC-4
Battery/Starting/Charging System
Tester ................................................SC-7, 12, 21
Blower motor ..................................................HA-95
Body alignment ...............................................BT-57
Brake booster .................................................BR-19
Brake control valve (Proportioning
valve)...........................................................BR-11
ALPHABETICAL INDEX
IDX-2

Brake fluid change ...........................................BR-7
Brake fluid level .............................................MA-25
Brake fluid level and line check .......................BR-7
Brake hydraulic line ..........................................BR-9
Brake inspection ............................................MA-25
Brake lines and cables inspection .................MA-25
Brake lining wear temporary checking ..........MA-26
Brake master cylinder ....................................BR-16
Brake pedal ....................................................BR-14
Bulb specifications ........................................EL-456
Bumper, front ..................................................BT-12
Bumper, rear ...................................................BT-15
BYPS/V - Wiring diagram ....................EC-587, 594
C
Camshaft inspection ......................................EM-42
Camshaft position sensor (PHASE) .............EC-342
Canister-See EVAP canister ..........................EC-32
Center bearing assembly (propeller
shaft) .............................................................PD-9
Center bearing disassembly (propeller
shaft) .............................................................PD-7
Center case (Transfer) ..................................TF-123
CHARGE - Wiring diagram ............................SC-20
Charging system ............................................SC-19
Chassis and body maintenance ....................MA-21
CHIME - Wiring diagram...............................EL-127
CIGAR - Wiring diagram ...............................EL-148
Cigarette lighter.............................................EL-148
Circuit breaker.................................................EL-16
CKPS - Wiring diagram ................................EC-334
Closed loop control (Left bank) ....................EC-491
Closed loop control (Right bank) .................EC-491
Closed throttle position switch .....................EC-431
Clutch drum (Transfer) ..................................TF-125
Clutch force release limit adjustment .............TF-39
Clutch pressure switch (Transfer) .................TF-111
Coil spring (front)..............................................SU-8
Coil spring (rear) ............................................SU-18
Collision diagnosis..........................................RS-59
Combination lamp, front, removal and
installation ...................................................BT-12
Combination lamp, rear, removal and
installation ...................................................BT-35
Combination meter..........................................EL-94
Combination meter removal and instal-
lation - See Instrument panel ......................BT-21
Combination switch .........................................EL-28
COMPAS - Wiring diagram ...........................EL-111
Compass .......................................................EL-110
Component Location (auto A/C).....................HA-27
Compression pressure ...................................EM-14
Compressor clutch removal and
installation .................................................HA-150
Compressor precaution ....................................HA-6
Compressor special service tool ....................HA-10
Connecting rod...............................................EM-65
Connecting rod bearing clearance.................EM-69
Connecting rod bushing clearance ................EM-70Connector inspection .......................................GI-21
Console box - See Instrument panel ..............BT-21
CONSULT for ABS .........................................BR-43
CONSULT for all-mode 4WD ..........................TF-30
CONSULT for engine .....................................EC-81
CONSULT-II general information .....................GI-38
Control valve (A/T) ........................................AT-301
Control valve (Transfer) ................................TF-128
Converter housing installation .......................AT-278
Coolant mixture ratio......................................MA-12
Coolant replacement ......................................MA-14
Cooling circuit (engine) ...................................LC-10
``Crankcase emission control system -
See positive crankcase ventilation''............EC-38
Crankshaft ......................................................EM-67
Crankshaft position sensor (POS) ...............EC-334
Crankshaft position sensor (POS)
chipping ....................................................EC-517
Crankshaft position sensor (REF) ................EC-510
Cruise control - See ASCD ...........................EL-221
Cylinder block ................................................EM-61
Cylinder head .................................................EM-38
Cylinder head bolt tightening .........................EM-49
D
Data link connector for Consult......................EC-81
Daytime light system.......................................EL-46
Daytime running light - See Daytime
light system .................................................EL-46
DEF - Wiring diagram ...................................EL-153
Detonation sensor - See Knock sensor .......EC-328
Diagnostic trouble code (DTC) for OBD
system ....................................................EC-8, 60
Diagnostic trouble code (DTC) inspec-
tion priority chart .......................................EC-116
Differential carrier assembly.....................PD-30, 57
Differential carrier disassembly ......................PD-44
Differential gear oil replacement ....................MA-24
Dimensions ......................................................GI-43
D/LOCK - Wiring diagram .............................EL-256
Dome light - See Interior lamp .......................EL-88
Door glass .......................................................BT-18
Door lock .........................................................BT-18
Door mirror ......................................................BT-56
Door trim .........................................................BT-30
Door, front .......................................................BT-18
Door, rear ........................................................BT-20
Drive belt inspection ......................................MA-13
Drive chain (Transfer) ...................................TF-125
Drive pinion diff. inspection ......................PD-23, 47
Drive pinion height ...................................PD-25, 53
Drive plate runout ..........................................EM-70
Drive shaft (front)............................................AX-10
Dropping resistor (A/T) ..................................AT-167
DTC work support ..........................................EC-93
DTRL - Wiring diagram ...................................EL-51
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ALPHABETICAL INDEX
IDX-3

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