Page 101 of 116

AUTOMATIC SPEED CONTROL DEVICE (A.S.C. D.)
Trouble-shooting (Cont'd)
Resume switch will not operate
Replace AS C D
control unit Check resume switch
h Accelerate switch will not owrate 11
Check accelerate switch circuit
v v Replace AS C D
control unit Check accelerate swttch
Engine hunts
Q
Check vacuum hose for breakage, cracks or
fracture
OK lNG Repair or replace hose
v
Does AS C D wire move smoothlv7
I NG v OK
Repair or replace wire
I
I Go to "Actuator Check" I
OK lNG Replace actuator
.I
Replace A S C D control unlt
RESUME SWITCH CIRCUIT CHECK
1 Turn ignition switch to "OFF"
2. Turn resume switch to "ON".
3. Check continuity between @ and 0
heck from harness side
on witch -+ OFF
M 0 h rn rn el e r SEL6120
ACCELERATE SWITCH CIRCUIT CHECK
1. Turn ignition switch to "OFF".
2. Turn accelerate switch to "ON"
3 Check continuity between @ and @
Check from harness %de
ignition switch + OFF
Accelerator witch -+ ON
SEL6130 Ohmmeter -
Large difference between set vehicle speed and
actual speed
I v
Check AS C D wire and actuator move
smoothlv
1 NG Replace wire 01
actuator
Check vacuum hose for breakage, cracks or
I fracture
4 NG
I OK Repair or replace hose
I Go to "Actuator Check" 1
4 NG
Replace actuator c OK Replace A.S C D
control unit
EL-I 01
Page 102 of 116

AUTOMATIC SPEED CONTROL DEVICE (A.S.C.D.)
- Trouble-shooting (Cont'd)
AIT model only
0 When A S C D is set while vehicle is operating
in
"0 D " range, 0 D will be cancelled and
shifting to
0 D cannot be made thereafter
0 While vehicle is being driven using AS C D in
"0 D "range, 0 D will not be cancelled even
if actual car speed is 6 kmlh (4 MPH) lower
than
set speed (Set speed cannot be main-
tained
)
1 Check 0 D cancel circuit for AS C D control unit I
Replace A S C D 0 Electroniccontrolled A/T
control unit Check harness between
lock-up control unit and
AS C D control unit
Check harness between
0 D. cancel solenoid.
i) D. cancel switch and
AS C D control unit
0 Conventional Ail
I
ELECTRONIC-CONTROLLED A/T
EQUIPPED MODEL (E4N71B)
Turn ignition switch to "OFF".
Check continuity between @ and @
Check from harness slde . .~
ignmon switch - OFF
SEL737D Ohmmeter
CONVENTIONAL A/T EQUIPPED
MODEL (4N71B)
Turn ignition switch to "ON"
Turn 0 D. cancel switch to "OFF".
Check voltage @ -0 and 0-0
Check from harness side A '- b9ndt'~~n~~~~i~hO_N 0 Fihz L
Approx 12v ,I { .__. _- I .__.__.__.- -' Volmeter SEL741D
A.S.C.D. Actuator Check
1. Check continuity between terminal @ and
Continuity exist
... O.K.
terminals 0, @ and 0.
CAUTION:
Do
not attempt to remove valves from actuator.
2 Connect battery (approx 12V) to harness
connector
of actuator as shown below, and
apply vacuum to actuator
If diaphragm moves smoothly, actuator IS O.K.
CAUTION.
When checking actuator by applying vacuum, do
not apply engine vacuum directly
as it IS too strong
to check actuator properly.
LA s c D actuator B,m, 112VI
SEL739D
EL-I 02
Page 110 of 116
,
TO TIME CON-
TROL UNIT
TO INST H LH (CHIME)
TO ENGINE
ROOM
H R H (UPHOLD RELAY)
TO ENGINE ROOM H L H IHEAO-
TO LIGHT SW TO LIGHT SW -
TO REAR
ro KEY sw
3OOM H R H A S C 0 RELAY1 To As sw (VACUUM ROOM H L H
PUMP RELAY)
(For time control system, headlamp system, AS C 0 and E F I system1
Page 111 of 116
![NISSAN 300ZX 1984 Z31 Electrical System Workshop Manual Diode
L & GLLxodelr
TO ENGINE ROOM
H R H (HORN RELAY]
HRH
ITHEFT
WARNING RELAY-11
TO ENGINE ROOM
TO THEFT WARNING
CONTROL UNIT
TO HORN SWJ
TO BACK DOOR SW TOTHEFT WARNING 3TlME CONT NISSAN 300ZX 1984 Z31 Electrical System Workshop Manual Diode
L & GLLxodelr
TO ENGINE ROOM
H R H (HORN RELAY]
HRH
ITHEFT
WARNING RELAY-11
TO ENGINE ROOM
TO THEFT WARNING
CONTROL UNIT
TO HORN SWJ
TO BACK DOOR SW TOTHEFT WARNING 3TlME CONT](/manual-img/5/567/w960_567-110.png)
Diode
L & GLLxodelr
TO ENGINE ROOM
H R H (HORN RELAY]
HRH
ITHEFT
WARNING RELAY-11
TO ENGINE ROOM
TO THEFT WARNING
CONTROL UNIT
TO HORN SWJ
TO BACK DOOR SW TOTHEFT WARNING 3TlME CONTROL UNIT CONTROL UNIT
TO ENGINE ROOM H R H ro INST H R H :DOOR WARNING LAMPI sw TOEFI H
TO LIGHT SW TO ENGINE ROOM H R H (POWER
STEERING SWI
TO INJECTOR BLOWER IFAN MOTOR RELAY)
(For theft warning system & E F I systeml
ode 6&
F model9
Not used
TOEFI H
TO ENGINE ROOM
HRH (POWER
STEERING SWI
TO LIGHT SW
TO FUSE
TO REAR
DEFOGGERRELAY
(For E F I system1 ode
TO TIME CONTROL
TO INST H
L H
TO ENGINE ROOM H
TO KEY SW UNIT
TO ENGINE ROOM H L H
(HEADLAMP MOTOR) (CHIME]
TO LIGHT SW
TO LIGHT SW IUPHOLD RELAY)
TO STEP LAMP TO DOOR SW R H
TO TIME
CONTROL UNIT
[For headlemp system & time control system)
Itode @
TO BACK DOOR ,LOCK SW
TO DOOR SW L H
TO DOOR SW R H
TO DOOR H LH
TO DOOR H
RH
TO VOICE WARNING UNIT AN0
TllEFT WARNING COhTROL UNIT
TO THEFT
WARNING
rCONTROL UNIT
TO BACK
DOOR SW
TO
DOOR SWRH
TO INST H R H (DOOR WARN-
ING LAMP)
TO TIME CONTROL UNIT
(Far voice warning system & theft warning system)
(Far theft warning system & tlme control system)
Turbocharger models
Nan turbocharger models
2+2 seater
2 seater
Door muror defogger swtch
A/T indicator lamp
RcmGlc
con1;a: miiiDi 8...itCh
0 D switch (AIT models)
Headlamp
cleaner switch
Shock absorber switch (Turbocharger models)
Body ground
Diode Diode
(Sf modcls)
Diode (GL and GLL models)
Diode (2+2 seater)
Theft warning control unit Seat belt switch R H (GLL models)
0, Sensor control amp (GLL models)
Parking brake switch
Radio amphfier
(GLL models)
Seal
bell switch L H (SF models) Seat belt switch L H (GL models) lo power seat harness (GLL models)
Body ground
(GLL models)
Didoe
(GL and GLL models)
Body ground (GLL models)
Body ground
(GLL models)
I
Page 114 of 116
0 To @I (White) 0 Diode (Voice warnmg system equipped
0 To @ (Blue) (GLL models) models except CLL models) 0 To @ Wile) 0 Speakcr R H (CLL models) 0 Jomt (POI 0, sensor warning lamp) 0 Glove box lamp switch @O Glove box lamp @ Hold relay (Canada models)
0 @9 To (Black) @9 . To 0 (White)
To @ (Blue) (GLL models)
Speak; L H (GLL models)
IUumlnation control switch
Instrument swtch
L H
Instrument swtch L H
Combination meter (Black)
Combination meter (While)
Combination meter (White)
Combination meter White)
Combination meter (White)
Combination meter (Blue)
Combmation meter (Black)
Chune Instiument switch
R H
Instrument switch R H
Needle type meter
Digital type meter
& Combmation gauge (CLL models)
@ Combmalion gauge (SF and CL models)
TO COMBINATION
METER (BRAKE WARNING LAMPI
TO ENGINE ROOM H (BRAKE FLUID LEVEL SWI
6 TO MAIN H IPARKING
BRAKE SW AND VOICE
WARNING UNIT1
[For voice warnmg system1