Page 1409 of 2395
SchematicNBEL0096
MEL837L
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Schematic
EL-224
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 1414 of 2395
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.
GI
MA
EM
LC
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
IDX
AUTOMATIC SPEED CONTROL DEVICE (ASCD)
Fail-safe System
EL-229
Page 1415 of 2395

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
Page 1416 of 2395
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.)
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-231