2001 INFINITI QX4 relay

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

ASCD BRAKE/STOP LAMP SWITCH CHECK=NBEL0218S04
1 CHECK ASCD BRAKE SWITCH CIRCUIT
1. Disconnect ASCD control unit harness connector.
2. Turn ignition switch ON.
3. Check voltage between ASCD control unit harness connector terminal 8 and ground.
SEL258WD
OK or NG
OK©GO TO 2.
NG©Check the following.
IASCD brake switch
Refer to ªElectrical Component Inspectionº (EL-239).
IPark/neutral position switch
Refer to ªElectrical Component Inspectionº (EL-239).
IPark/neutral position relay
IHarness for open or short
2 CHECK STOP LAMP SWITCH CIRCUIT
1. Disconnect ASCD control unit harness connector.
2. Check voltage between ASCD control unit harness connector terminal 23 and ground.
SEL259WB
Refer to wiring diagram in EL-226.
OK or NG
OK©ASCD brake/stop lamp switch is OK.
NG©Check the following.
I10A fuse [No. 14, located in the fuse block (J/B)]
IHarness for open or short between ASCD control unit and stop lamp switch
IHarness for open or short between fuse and stop lamp switch
IStop lamp switch
Refer to ªElectrical Component Inspectionº (EL-239).
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AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses (Cont'd)
EL-233

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

System DescriptionNBEL0102Power is supplied at all times
Ifrom 40A fusible link (letterf, located in the fuse and fusible link box)
Ito circuit breaker terminal 1
Ithrough circuit breaker terminal 2
Ito power window relay terminal 3,
Ito front power window main switch terminal 4, and
Ito front power window switch RH terminal 6.
With ignition switch in ON or START position, power is supplied
Ithrough 7.5A fuse [No. 11, located in the fuse block (J/B)]
Ito power window relay terminal 2, and
Ito smart entrance control unit terminal 33.
Ground is supplied to power window relay terminal 1
Ithrough body grounds M4, M66 and M147.
The power window relay is energized and power is supplied
Ithrough power window relay terminal 5
Ito front power window main switch terminal 11,
Ito front power window switch RH terminal 13,
Ito rear power window switch LH and RH terminals 5.
MANUAL OPERATIONNBEL0102S01Front Door LHNBEL0102S0101Ground is supplied
Ito front power window main switch terminal 5
Ithrough body grounds M77 and M111.
WINDOW UP
When the front LH switch in the front power window main switch is pressed in the up position, power is sup-
plied
Ito front power window regulator LH terminal 1
Ithrough front power window main switch terminal 2.
Ground is supplied
Ito front power window regulator LH terminal 3
Ithrough front power window main switch terminal 3.
Then, the motor raises the window until the switch is released.
WINDOW DOWN
When the LH switch in the front power window main switch is pressed in the down position, power is supplied
Ito front power window regulator LH terminal 3
Ithrough front power window main switch terminal 3.
Ground is supplied
Ito front power window regulator LH terminal 1
Ithrough front power window main switch terminal 2.
Then, the motor lowers the window until the switch is released.
Front Door RHNBEL0102S0102Ground is supplied
Ito front power window main switch terminal 5
Ithrough body grounds M77 and M111.
NOTE:
Numbers in parentheses are terminal numbers, when power window switch is pressed in the UP and DOWN
positions respectively.
FRONT POWER WINDOW MAIN SWITCH OPERATION
When front RH switch in the front power window main switch is pressed UP or DOWN, a signal is supplied
Ithrough front power window main switch terminal 8
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POWER WINDOW
System Description
EL-241

Ito front power window switch RH terminal 11.
The subsequent operation is the same as the front power window switch RH operation.
FRONT POWER WINDOW SWITCH RH OPERATION
Power is supplied
Ithrough front power window switch RH (5, 4)
Ito front power window regulator RH (1, 3).
Ground is supplied
Ito front power window regulator RH (3, 1)
Ithrough front power window switch RH (4, 5)
Ito front power window switch RH terminal 12
Ithrough front power window main switch terminal 1.
Then, the motor raises or lowers the window until the switch is released.
Rear Door LHNBEL0102S0104Ground is supplied
Ito front power window main switch terminal 5
Ithrough body grounds the M77 and M111.
NOTE:
Numbers in parentheses are terminal numbers, when the power window switch is pressed in the UP and
DOWN positions.
FRONT POWER WINDOW MAIN SWITCH OPERATION
Power is supplied
Ithrough front power window main switch terminal (13, 12)
Ito rear power window switch LH terminal (3, 4)
The subsequent operation is the same as the rear power window switch LH operation.
REAR POWER WINDOW SWITCH LH
Power is supplied
Ithrough rear power window switch LH (1, 2)
Ito rear power window regulator LH (1, 2)
Ground is supplied
Ito rear power window regulator LH (2, 1)
Ithrough rear power window switch LH (2, 1)
Ito rear power window switch LH terminal (4, 3)
Ithrough front power window main switch terminal (12, 13)
Then, the motor raises or lowers the window until the switch is released.
Rear Door RHNBEL0102S0105Rear door RH windows will rise and lower in the same manner as the rear door LH window.
AUTO OPERATIONNBEL0102S02The power window AUTO feature enables the driver or front passenger to open or close the driver's and front
passenger's window without holding the window switch in the up or down position.
The AUTO feature only operates on the driver's and front passenger's window upward and downward move-
ment.
POWER WINDOW LOCKNBEL0102S03The power window lock is designed to lock operation of all windows except for driver's door window.
When the lock switch is pressed to lock position, the ground of the front and rear power window switches, in
the power window main switch, is disconnected. This prevents the power window motors from operating.
RETAINED POWER OPERATIONNBEL0102S04When the ignition switch is turned to OFF position from ON or START position, power is supplied for 45 sec-
onds
Ito power window relay terminal 2
Ifrom smart entrance control unit terminal 5.
Ground is always supplied
POWER WINDOW
System Description (Cont'd)
EL-242

Ito power window relay terminal 1
Ithrough body grounds.
When power and ground are supplied, the power window relay continues to be energized, and the power win-
dow can be operated.
The retained power operation is canceled when the driver or passenger side door is opened.
INTERRUPTION DETECTION FUNCTIONNBEL0102S05Front power window main switch and front power window switch RH monitor the power window regulator motor
operation and the power window position (full closed or other) for driver's and passenger's power window by
the signals from encoder and limit switch in front power window regulator LH or RH.
When front power window main switch or front power window switch RH detects interruption during the fol-
lowing close operation in the driver's or front passenger's side door,
Iautomatic close operation when ignition switch is in the ªONº position
Iautomatic close operation during retained power operation
front power window main switch or front power window switch RH controls driver's or front passenger's power
window regulator motor for open and the power window will be lowered about 150 mm (5.91 in).
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POWER WINDOW
System Description (Cont'd)
EL-243

Trouble DiagnosesNBEL0221
Symptom Possible cause Repair order
None of the power windows can be
operated using any switch.1. 7.5A fuse, 40A fusible link
2. M145 circuit breaker
3. Power window relay
4. M145 circuit breaker circuit
5. Power window relay circuit
6. Ground circuit
7. Power window main switch1. Check 7.5A fuse [No. 11, located in fuse block
(J/B)], 40A fusible link (letterf, located in fuse and
fusible link box).
2. Check M145 circuit breaker.
3. Check power window relay.
4. Check the following.
a. Harness between M145 circuit breaker and 40A fus-
ible link
b. Harness between M145 circuit breaker and front
power window main switch
5. Check the following.
a. Harness between 7.5A fuse and power window relay
b. Harness between M145 circuit breaker and power
window relay
6. Check the following.
a. Ground circuit of power window main switch terminal
5
b. Power window relay ground circuit
7. Check power window main switch.
Driver side power window cannot
be operated but other windows can
be operated.1. Driver side power window regu-
lator circuit
2. Driver side power window regu-
lator
3. Power window main switch1. Check harness between power window main switch
and driver side power window regulator for open or
short circuit.
2. Check driver side power window regulator.
3. Check power window main switch.
Passenger side power window can-
not be operated but other window
can be operated.1. Power supply for front power
window switch RH
2. Front power window switch RH
ground circuit
3. Front power window switch RH
circuit
4. Front power window regulator
RH circuit
5. Front power window regulator
RH
6. Front power window main
switch
7. Front power window switch RH1. Check power supply for front power window switch
RH terminals 6 and 13.
2. Check front power window switch RH ground circuit.
3. Check harness between front power window switch
RH and power window main switch.
4. Check harness between front power window switch
RH and front power window regulator RH for open
or short circuit.
5. Check front power window regulator RH.
6. Check front power window main switch.
7. Check front power window switch RH.
One or more rear power windows
except front window cannot be
operated.1. Rear power window switches
2. Rear power window regulators
3. Power window main switch
4. Rear power window circuit1. Check rear power window switches.
2. Check rear power window regulator.
3. Check power window main switch.
4. Check the following.
a. Harness between the rear power window switches
terminal 5 and power window relay
b. Harnesses between power window main switch and
rear power window switches for open/short circuit
c. Harnesses between rear power window switches
and rear power window regulator for open/short cir-
cuit
Power windows except driver's
side window cannot be operated
using power window main switch
but can be operated by power win-
dow switches.1. Power window main switch 1. Check power window main switch.
Driver side power window auto-
matic operation does not function
properly.1. Power window main switch
2. Encoder and limit switch1. Check power window main switch.
2. Check encoder and limit switch. (EL-252)
POWER WINDOW
Trouble Diagnoses
EL-250

Symptom Possible cause Repair order
Front passenger side power win-
dow automatic operation does not
function properly.1. Front power window switch RH
2. Encoder and limit switch1. Check front power window switch RH.
2. Check encoder and limit switch. (EL-252)
Retained power operation does not
operate properly.1. RAP signal circuit
2. Driver or passenger side door
switch circuit
3. Smart entrance control unit1. Check harness between power window relay termi-
nal 2 and smart entrance control unit terminal 5 for
open or short circuit.
2. Check the following.
a. Harness between smart entrance control unit and
driver or passenger side door switch for short circuit
b. Driver or passenger side door switch ground circuit
c. Driver or passenger side door switch
3. Check smart entrance control unit. (EL-324)
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POWER WINDOW
Trouble Diagnoses (Cont'd)
EL-251