power steering INFINITI QX4 2001 Factory Owner's Manual

System DescriptionNBEL0216Refer to Owner's Manual for ASCD operating instructions.
POWER SUPPLY AND GROUNDNBEL0216S01Power is supplied at all times:
Ithrough 10A fuse [No. 14, located in the fuse block (J/B)]
Ito the stop lamp switch terminal 1, and
Ithrough 7.5A fuse (No. 52, located in fuse and fusible link box)
Ito the horn relay terminals 1 and 3.
When ignition switch is in the ON or START position, power is supplied:
Ithrough 7.5A fuse [No. 11, located in the fuse block (J/B)]
Ito ASCD brake switch terminal 1 and
Ito ASCD control unit terminal 5,
Ithrough 10A fuse [No. 18, located in the fuse block (J/B)]
Ito park/neutral position relay terminal 1,
Ithrough 10A fuse [No. 8, located in the fuse block (J/B)]
Ito combination meter terminal 66, and
When park/neutral position switch is in the P or N position, ground is supplied:
Ito park/neutral position relay terminal 2
Ithrough park/neutral position switch and body grounds B55 and B75.
When ASCD main switch is depressed (ON), ground is supplied:
Ito ASCD control unit terminal 9
Ifrom ASCD steering switch terminal 4
Ito ASCD steering switch terminal 5
Ithrough body grounds M4, M66 and M147
then ASCD control unit holds CRUISE condition and illuminates CRUISE indicator.
Ground is supplied:
Ifrom ASCD control unit terminal 15
Ito combination meter terminal 46.
OPERATIONNBEL0216S02Set OperationNBEL0216S0201To activate the ASCD, all following conditions must exist.
IGround supply to ASCD control unit terminal 9 (Main switch is in ON position.)
IPower supply to ASCD control unit terminal 8 (Brake pedal is released and A/T selector lever is in other
than P and N position.)
IVehicle speed is between 40 km/h (25 MPH) and 144 km/h (89 MPH). (Signal from combination meter)
When the SET/COAST switch is depressed, power is supplied:
Ifrom ASCD steering switch terminal 2
Ito ASCD control unit terminal 11.
And then ASCD pump is activated to control throttle wire and ASCD control unit supply ground
Ito combination meter terminals 51 to illuminate SET indicator.
A/T Overdrive Control during Cruise Control DrivingNBEL0216S0202When the vehicle speed is approximately 3 km/h (2 MPH) below set speed, a signal is sent
Ifrom ASCD control unit terminal 10
Ito TCM (transmission control module) terminal 24.
When this occurs, the TCM (transmission control module) cancels overdrive.
After vehicle speed is approximately 1 km/h (1 MPH) below set speed, overdrive is reactivated.
ASCD Shifting ControlNBEL0216S0203During ASCD cruise, ASCD control unit controls A/T shifting to avoid uncomfortable shifting.
This is used to control the signals below.
IThrottle position sensor from ECM
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
System Description
EL-222

IA/T shift solenoid valve A
Coast OperationNBEL0216S0204When the SET/COAST switch is depressed during cruise control driving, ASCD actuator returns the throttle
cable to decrease vehicle set speed until the switch is released. And then ASCD will keep the new set speed.
Accel OperationNBEL0216S0205When the RESUME/ACCEL switch is depressed, power is supplied
Ifrom ASCD steering switch terminal 3
Ito ASCD control unit terminal 24.
If the RESUME/ACCEL switch is depressed during cruise control driving, ASCD actuator pulls the throttle cable
to increase the vehicle speed until the switch is released or vehicle speed is reached to maximum controlled
speed by the system. And then ASCD will keep the new set speed.
Cancel OperationNBEL0216S0206When any of following condition exists, cruise operation will be canceled.
ICANCEL switch is depressed. (Power supply to ASCD control unit terminals 11 and 24)
IBrake pedal is depressed. (Power supply to ASCD control unit terminal 23 from stop lamp switch)
IBrake pedal is depressed or A/T selector lever is shifted to P or N position. (Power supply to ASCD con-
trol unit terminal 8 is interrupted.)
If MAIN switch is turned to OFF during ASCD is activated, all of ASCD operation will be canceled and vehicle
speed memory will be erased.
Resume OperationNBEL0216S0207When the RESUME/ACCEL switch is depressed after cancel operation other than depressing MAIN switch is
performed, vehicle speed will return to last set speed. To resume vehicle set speed, vehicle condition must
meet following conditions.
IBrake pedal is released.
IA/T selector lever is in other than P and N position.
IVehicle speed is between 40 km/h (25 MPH) and 144 km/h (89 MPH).
ASCD PUMP OPERATIONNBEL0216S03The ASCD pump consists of a vacuum motor, an air valve and a release valve. When the ASCD activates,
power is supplied
Ifrom terminal 12 of ASCD control unit
Ito ASCD pump terminal 1.
Ground is supplied to vacuum motor, air valve and release valve from ASCD control unit depending on the
operated condition as shown in the below table.
The pump is connected to ASCD actuator by vacuum hose. When the ASCD pump is activated, the ASCD
pump vacuum the diaphragm of ASCD actuator to control throttle cable.
Air valve (*1) Release valve (*1) Vacuum motorActuator inner pres-
sure
ASCD not operating Open Open Stopped Atmosphere
ASCD operatingReleasing throttle
cableOpen Closed Stopped Vacuum
Holding throttle
positionClosed Closed Stopped Vacuum (*2)
Pulling throttle cable Closed Closed Operated Vacuum
*1: When power and ground is supplied, valve is closed.
*2: Set position held.
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)
System Description (Cont'd)
EL-223

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

ASCD STEERING SWITCH CHECK=NBEL0218S05
1 CHECK ASCD STEERING SWITCH CIRCUIT FOR ASCD CONTROL UNIT
Check voltage between ASCD control unit harness connector terminals and ground.
SEL260WC
Refer to wiring diagram in EL-226.
OK or NG
OK©ASCD steering switch is OK.
NG©GO TO 2.
2 CHECK POWER SUPPLY FOR ASCD STEERING SWITCH
Does horn work?
Ye s©GO TO 3.
No©Check the following.
I7.5A fuse (No. 52, located in the relay box)
IHorn relay
IHorn circuit
3 CHECK ASCD STEERING SWITCH
1. Disconnect ASCD steering switch.
2. Check continuity between terminals by pushing each switch.
SEL764WA
OK or NG
OK©Check harness for open or short between ASCD steering switch and ASCD control unit.
NG©Replace ASCD steering switch.
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses (Cont'd)
EL-234

NOTE:
After replacing IVCS unit, set up the replaced IVCS unit. Refer
to ªSystem Setting (When IVCS Unit is Replaced.)º in EL-381.
SYMPTOM CHART 2 (BASED ON SYMPTOM)NBEL0184S04Before referencing this chart, confirm the operation of the indicator
lamps. Refer to ªPRELIMINARY CHECKº in EL-369. If the indica-
tors show the system is malfunctioning, perform the self-diagnosis
using CONSULT-II.
Symptom Diagnoses/service procedure Reference page
ªMAYDAYº, ªINFORMATIONº, ªRE-DIALº,
ªNO SERVICEº indicator lamps do not illu-
minate when ignition switch is turned to ON
position. (Bulb check is NG.)1. Power supply and ground circuit for IVCS unit check EL-371
2. Indicator lamps check EL-372
Mayday/Information call does not operate.1. IVCS switch check EL-373
2. INFINITI Communicator operation check in demonstration
modeEL-379
Remote door unlocking function does not
operate.1. Back door handle switch check EL-374
2. Remote door unlock function check EL-374
3. INFINITI Communicator operation check in demonstration
modeEL-379
Stolen vehicle tracking function does not
operate.1. Stolen vehicle tracking setting check
(Check whether the function is disabled or not.)EL-375
2. INFINITI Communicator operation check in demonstration
modeEL-379
Alarm notification function does not oper-
ate.1. Alarm notification setting check
(Check whether the function is disabled or not.)EL-375
2. INFINITI Communicator operation check in demonstration
modeEL-379
Hands free telephone cannot be operated
by using steering switch.
(Cellular phone operates properly by using
handset.)1. Telephone steering switch check EL-377
No sounds related to the telephone are
heard from Front RH speaker. (If the audio
does not operate properly, check the audio
system.)1. Check harness for open or short between IVCS unit and
audio unit.Ð
The ªNO SERVICEº indicator lamp is not
turned off. (Even if a contract with tele-
phone carrier has not been made, the indi-
cator lamp remains illuminated.)1. Make sure the vehicle is in an area with cellular service. Ð
2. Check cellular phone antenna feeder cable connection. Ð
Cellular phone does not operate properly.1. Check hand set connector connection. Ð
2. Check hand set. Ð
No sound is transmitted to the other party
by hands free telephone.1. Check harness for open or short between IVCS unit and
microphone.Ð
2. Replace microphone. (IVCS switch assembly) Ð
INFINITI COMMUNICATOR (IVCS)
Trouble Diagnoses (Cont'd)
EL-370

TELEPHONE STEERING SWITCH CHECK=NBEL0184S14
1 CHECK POWER SUPPLY FOR STEERING SWITCH
Check power supply for steering switch.
Does horn work?
Ye s©Check the following.
I10A fuse (No. 54, located in fuse and fusible link box)
IHorn relay
IHarness for open or short
No©GO TO 2.
2 CHECK STEERING SWITCH SUB-HARNESS
1. Remove driver's air bag module. For removal procedure, refer to RS section.
2. Check steering switch sub-harness for open or short and ground screw.
For details of the harness circuit, refer to ªSTEERING SWITCHº, EL-30.
OK or NG
OK©Check harness for open or short between telephone steering switch and IVCS unit. If the
circuit is OK, replace telephone steering switch.
NG©Replace or repair the harness.
Trouble Diagnoses for Intermittent IncidentNBEL0185DESCRIPTIONNBEL0185S01An intermittent incident may be occurring if all of the following conditions exist.
IBoth ªMAYDAYº emergency and ªINFORMATIONº indicators have shown that the system is malfunction-
ing.
ICONSULT-II self-diagnosis result screen indicates a trouble code with ªTIME=1orgreaterº.
IThe INFINITI Communicator system has not been previously serviced.
To find out the cause of a malfunction, follow the procedures shown below.
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INFINITI COMMUNICATOR (IVCS)
Trouble Diagnoses (Cont'd)
EL-377

Code Section Wiring Diagram Name
NAVI EL Navigation System
NONDTC AT Non-detectable Items
O2H1B1 EC Heated Oxygen Sensor 1 Heater
(Front) (Bank 1)
O2H1B2 EC Heated Oxygen Sensor 1 Heater
(Front) (Bank 2)
O2H2B1 EC Heated Oxygen Sensor 2 Heater
(Rear) (Bank 1)
O2H2B2 EC Heated Oxygen Sensor 2 Heater
(Rear) (Bank 2)
O2S1B1 EC Heated Oxygen Sensor 1 (Front)
(Bank 1)
O2S1B2 EC Heated Oxygen Sensor 1 (Front)
(Bank 2)
O2S2B1 EC Heated Oxygen Sensor 2 (Rear)
(Bank 1)
O2S2B2 EC Heated Oxygen Sensor 2 (Rear)
(Bank 2)
OVRCSV AT Overrun Clutch Solenoid Valve
P/ANT EL Power Antenna
PGC/V EC EVAP Canister Purge Volume
Control Solenoid Valve
PHASE EC Camshaft Position Sensor
(PHASE)
PNP/SW EC Park/Neutral Position Switch
PNP/SW AT Park/Neutral Position Switch
POS EC Crankshaft Position Sensor
(CKPS) (POS)
POWER EL Power Supply Routing
PRE/SE EC EVAP Control System Pressure
Sensor
PST/SW EC Power Steering Oil Pressure
Switch
REF EC Crankshaft Position Sensor
(CKPS) (REF)
REMOTE EL Audio (Remote Control Switch)
RP/SEN EC Refrigerant Pressure
S/SIG EC Start Signal
S/VCSW EC Swirl Control Valve Control
Vacuum Check Switch
SEAT EL Power Seat
SHIFT AT A/T Shift Lock System
SROOF EL Sunroof
SRS RS Supplemental Restraint SystemCode Section Wiring Diagram Name
SSV/A AT Shift Solenoid Valve A
SSV/B AT Shift Solenoid Valve B
START SC Starting System
STOP/L EL Stop lamp
SWL/V EC Swirl Control Valve Control Sole-
noid Valve
TAIL/L EL Parking, License and Tail Lamps
TCCSIG AT A/T TCC Signal (Lock up)
TCV AT Torque Converter Clutch Solenoid
Valve
T/F TF Transfer
TFTS EC Tank Fuel Temperature Sensor
THEFT EL Theft Warning System
TLID EL Glass Hatch Opener
TP/SW EC Throttle Position Switch
TPS AT Throttle Position Sensor
TPS EC Throttle Position Sensor
TRNSMT EL Integrated HOMELINKYTrans-
mitter
TRSA/T AT Turbine Revolution Sensor
TURN EL Turn Signal and Hazard Warning
Lamps
VIAS/V EC Variable Induction Air Control Sys-
tem
VSS EC Vehicle Speed Sensor
VSSA/T AT Vehicle Speed Sensor A/T (Revo-
lution Sensor)
VSSMTR AT Vehicle Speed Sensor MTR
WARN EL Warning Lamps
WINDOW EL Power Window
WIP/R EL Rear Wiper and Washer
WIPER EL Front Wiper and Washer
WIRING DIAGRAM CODES (CELL CODES)
EL-458

9. Remove the crankshaft position sensors (REF and POS).
10. Remove drive belts and idler pulley with bracket.
11. Remove power steering oil pump, then put it aside holding with
a suitable wire.
12. Remove alternator.
SEM605G
13. Install engine slingers.
14. Remove front propeller shaft. (4WD)
Refer to PD-6, ªRemoval and Installationº.
15. Remove exhaust front tube heat insulators, then remove rear
heat oxygen sensors.
16. Remove exhaust front tube from both sides.
Refer to FE-8, ªRemoval and Installationº.
17. Remove front final drive. (4WD)
Refer to PD-18, ªRemoval and Installationº.
18. Remove starter motor.
19. Disconnect oil pressure switch harness connector.
SEM528G
20. Loosen and disconnect the bolts fixing the steering column
assembly lower joint and the power steering gear.
SEM471G
21. Set a suitable transmission jack under the front suspension
member and hoist engine with engine slingers.
EMQ0357D
22. Remove front engine mounting nuts from both sides.
OIL PAN
Removal (Cont'd)
EM-16

CAUTION:
IAfter removing timing chain, do not turn crankshaft and
camshaft separately, or valves will strike piston heads.
IWhen installing camshafts, chain tensioners, oil seals, or
other sliding parts, lubricate contacting surfaces with new
engine oil.
IApply new engine oil to bolt threads and seat surfaces
when installing camshaft sprockets and crankshaft pulley.
IBefore disconnecting fuel hose, release fuel pressure.
Refer to EC-39, ªFuel Pressure Releaseº.
IBe careful not to damage sensor edges.
IDo not spill engine coolant on drive belts.
RemovalNBEM00121. Release fuel pressure.
Refer to EC-39, ªFuel Pressure Releaseº.
2. Remove battery.
3. Remove radiator.
Refer to LC-19, ªREMOVAL AND INSTALLATIONº.
4. Drain engine oil.
5. Remove drive belts and idler pulley with brackets.
6. Remove cooling fan with bracket.
7. Remove engine cover.
8. Remove air duct with air cleaner case, collector, blow-by hose,
vacuum hoses, fuel hoses, water hoses, wires, harnesses,
connectors and so on.
9. Remove the air compressor, and tie it down using rope or the
like to keep it from interfering.
10. Remove the power steering oil pump and reservoir tank. Tie
them down using rope or the like to keep them from interfer-
ing.
11. Remove alternator.
12. Remove the following.
IVacuum gallery
IWater bypass pipe
IBrackets
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TIMING CHAIN
Components (Cont'd)
EM-23