INFINITI QX4 2001 Factory Service Manual
QX4 2001
INFINITI
INFINITI
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INFINITI QX4 2001 Factory Service Manual
Page 1380 of 2395
MEL187M
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
AUTOMATIC DRIVE POSITIONER
Wiring Diagram Ð AUT/DP Ð (Cont'd)
EL-195
Page 1410 of 2395
Wiring Diagram Ð ASCD ÐNBEL0097FIG. 1NBEL0097S01
MEL838L
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Wiring Diagram Ð ASCD Ð
EL-225
Page 1411 of 2395
FIG. 2NBEL0097S02
MEL839L
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Wiring Diagram Ð ASCD Ð (Cont'd)
EL-226
Page 1412 of 2395
FIG. 3NBEL0097S03
MEL840L
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Wiring Diagram Ð ASCD Ð (Cont'd)
EL-227
Page 1413 of 2395
FIG. 4NBEL0097S04
MEL841L
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Wiring Diagram Ð ASCD Ð (Cont'd)
EL-228
Page 1417 of 2395
POWER SUPPLY AND GROUND CIRCUIT CHECK=NBEL0218S03
1 CHECK POWER SUPPLY CIRCUIT FOR ASCD CONTROL UNIT
1. Disconnect ASCD control unit harness connector.
2. Turn ignition switch ON.
3. Check voltage between ASCD control unit harness connector terminal 5 and ground.
SEL256WB
Refer to wiring diagram in EL-227.
Ye s©GO TO 2.
No©Check the following.
I7.5A fuse (No. 11 located in the fuse block)
IHarness for open or short
2 CHECK GROUND CIRCUIT FOR ASCD CONTROL UNIT
Check continuity between ASCD control unit harness connector terminal 17 and body ground.
SEL257WB
Refer to wiring diagram in EL-227.
Ye s©Power supply and ground circuit is OK.
No©Repair harness.
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses (Cont'd)
EL-232
Page 1418 of 2395

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).
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses (Cont'd)
EL-233
Page 1419 of 2395
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
Page 1420 of 2395

VEHICLE SPEED SENSOR CHECK=NBEL0218S06
1 CHECK SPEEDOMETER OPERATION
Does speedometer operate normally?
Ye s©GO TO 2.
No©Check speedometer and vehicle speed sensor circuit. Refer to wiring diagram in EL-228.
2 CHECK VEHICLE SPEED INPUT
1. Apply wheel chocks and jack up drive wheel.
2. Disconnect ASCD control unit harness connector.
3. Check voltage between control unit terminal 22 and ground with turning drive wheel slowly by hand.
SEL263WB
Refer to wiring diagram in EL-227.
Ye s©Vehicle speed sensor is OK.
No©Check harness for open or short between ASCD control unit terminal 22 and combination
meter terminal 13.
ASCD PUMP CIRCUIT CHECKNBEL0218S07
1 CHECK ASCD PUMP
1. Disconnect ASCD pump connector.
2. Measure resistance between ASCD pump terminals 1 and 2, 3, 4.
SEL262WB
Refer to wiring diagram in EL-227.
OK or NG
OK©GO TO 2.
NG©Replace ASCD pump.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Trouble Diagnoses (Cont'd)
EL-235
Page 1430 of 2395
Wiring Diagram Ð WINDOW ÐNBEL0104
MEL008O
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
POWER WINDOW
Wiring Diagram Ð WINDOW Ð
EL-245