1989 MITSUBISHI GALANT automatic

13-336AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
Probable cause1 Check chart No.1 Remedy
l The set vehicle speed variesMalfunction of the ve-No.4Repair the vehicle speec
greatly upward or downward.hicle speed sensor cir-sensor system, or re-l “Hunching” (repeated alternatingcuit place the part.
acceleration and deceleration) oc-
curs after setting is made.
Malfunction of the spee-dometer cable or spee-dometer drive gear
Actuator circuit poor
contact
Malfunction of the ac-
tuator
No.5Repair the actuator sys-tern or replace the part.
Malfunction of the ECU
-Replace the ECU.
The auto-cruise control system is notDamaged or discon-If the input check codeRepair the harness or re
canceled when the brake pedals isnetted wiring of the stopNo.23 indicates a mal- place the stop light
depressed.light switch input circuit; function. No.6-1switch.
brake switch (for auto-
cruise control) malfunc-
tion (short-circuit)
Actuator drive circuit
No.5Repair the harness or reshort-circuit.place the actuator.
Malfunction of the ECU
-Replace the ECU.
-he auto-cruise control system is notDamaged or discon-If the input check codeRepair the harness, or:anceled when the clutch pedal isnetted wiring of clutchNo.23 indicates a mal- repair or replace thedepressed. (vehicles with a manual pedal position switchfunction. No.6-3
clutch pedal position
ransaxle)input circuit switch.
It is canceled, however, when the
)rake pedal is depressed.) Clutch pedal positionswitch improper installa-
tion (won’t switch ON)
Malfunction of the ECU-Replace the ECU.
-he auto-cruise control system is notDamaged or discon-If the input check codeRepair the harness, orzanceled when the shift lever isnetted wiring of park/No.23 indicates a mal- repair or replace thenoved to the “N” position. (vehicles
neutral position switch function. No.6-2park/neutral positionvith an automatic transaxle)input circuit switch.t is canceled, however, when theIrake pedal is depressed.)Improper adjustment of
park/neutral position
switch
Malfunction of the ECU-Replace the ECU.
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AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
13-337
Trouble symptom
Cannot decelerate by using the
SET switch
Probable cause
Check chart No.Remedy
Temporary damagedNo. 2Repair the harness or
or disconnected wir-
replace the SET
ing of SET switchswitch.
Actuator circuit poorNo. 5Repair the harness or
replace the actuator.
Malfunction of the
1 Malfunction of the
ECU
-Replace the ECU.
Cannot accelerate or resume
speed by using the RESUME
switch.
Damaged or discon- No. 3 netted
wiring, or
short-circuit, of
RE-
SUME switch input
circuit Repair the harness or
replace the RESUME
switch.
Actuator circuit poor No. 5iRepair the harness or
; contact replace the actuator.
Malfunction of the
actuator
,
Malfunction of the-Replace the ECU.
ECU
Jute-cruise control system can be i Malfunction of the No. 4
Repair the vehicle-
set while traveling at a vehiclevehicle-speed sensor speed sensor system,
speed of less than 40 km/h (25circuitor replace the part.
nph), or there is no automatic
zancellation at that speed.
Malfunction of the
speedometer cable or
the speedometer
drive gear
Malfunction of the
’ ECU
-Replace the ECU.
The indicator light of the combination Damaged or discon-
neter does not illuminate. netted bulb of
But auto-cruise control system isindicator light
lormal.1
-Repair the harness or
replace the light
bulb.
Harness damaged or
disconnected
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13-340AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
2. CHECKING THE SET SWITCH CIRCUIT
ECU
Description of operation
When the SET switch is switched ON (at the
vehicle speed desired to be maintained, and with
the main switch of the cruise-control switches ON)
that vehicle speed is maintained as a constant
speed.
Furthermore, the constant speed is gradually re- duced
(the “coasting” feature) when the SET switch is pressed and held while the vehicle is
traveling at the previously set constant speed, and,
when the SET switch is released, tne vehicle then
maintains that newly set constant speed (th
e
speed at which the SET switch was
released).
Current flows to the control unit, the cruise control switch (“SET”), and to ground.
Troubleshooting hint
Diagnostic-No.1 5 (automatically cancelled)
ECU terminal voltage
Terminal
No.SignalConditions Terminal voltage
5SET switch
When the SET switch is switched ON ov
When the SET switch is switched OFF
12v
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13-342AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
4. CHECKING THE VEHICLE-SPEED SENSOR CIRCUIT
Combination meter
E-2
Description of operation
The vehicle-speed sensor is installed within the speedometer; it sends to the control unit pulsesignals that are proportional to the rotation speed
(i.e., the vehicle speed) of the transmission’s
output gear. This vehicle-speed sensor is the reed switch type
of sensor; it generates four pulse signals for eachrotation of the speedometer’s driven gear.
Troubleshooting hint
Diagnostic-No.1 2 (automatically cancelled)
ECU terminal voltage Terminal
No.SignalConditions Terminal voltage
15
Vehicle-speed sensor
Move the vehicle forward slowly.
ov -3V or 0.7v
-Flashing-+ higher
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1

13-344AUTO-CRUISE CONTROL SYSTEM - Troubleshooting
Description of operation
* -LimA switch
DC motor
7 coil
-
1. When (with the main switch ON) the driver switches ON the SET switch when the pre-
scribed vehicle speed is reached, the control
unit sends current to the electromagnetic clutch
coil of the actuator, thus attracting the clutch plate, and also illuminating the auto-cruise in-
dicator light, Then, when the ring gear of the planetary pinion is secured, the control motor at
the same time causes the DC motor to be
switched ON, and the DC motor operates at high speed.
2.The rotation of the DC motor is, as described in
the illustration above, transmitted to the worm
gear, and thereafter to the worm wheel, the
sun gear, and the planetary pinion in that
sequence. Because the ring gear is secured at
this time, the planetary pinion rotates while revolving around the sun gear. Because the
planetary pinion is installed to the carrier, both
the carrier and the selecotr drive shaft unified
with it, as well as the selector, are caused to rotate.
3.The switching of the direction (PULL or REL.) of
rotation of the selector is accomplished by reversing the direction of current flow to the
motor, and this is automatically regulated by
the control unit.
4. The current flow to the electromagnetic clutch
is interrupted if the driver switches OFF the
main switch, or if the operation of the auto
cruise control system is
cancelled as a result of
the input of a cancel signal to the control unit because the stop light switch, clutch pedal posi-
tion switch (for a manual transaxle) or the park/ neutral position switch (for an automatic trans-
axle) is activated.
5. As a result of the interruption of current to the
electromagnetic clutch, the clutch plate is
caused to return from the electromagnetic
clutch side to the ring gear side by the force of
the spring, and therefore the ring gear be-
comes free.
6. When the ring gear becomes free, the plane-
tary pinion becomes free relative to the sungear, and thus the selector is caused, by the
return spring installed to the selector part, to
return to its original position.
Troubleshooting hint
Diagnostic-No.1 1 (automatically cancelled)
ECU terminal voltage
Terminal
NO.Signal ConditionsTerminal voltage
8Transistor for electro-When the cruise-control switch (main switch) is switch-
magnetic clutch coiled ON o
v
9DC motor drive (“PULL”
During acceleration by RESUME switch
side) 12v
DC motor drive (“REL.”
During speed reduction (coasting) by SET switch
side)ov
20DC motor drive (“PULL” During acceleration by RESUME switch
side) o
v
DC motor drive (“REL.”
During speed reduction (coasting) by SET switch
side) 12v
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AUTO-CRUISE CONTROL SYSTEM - Troubleshooting13-345
6-1. CHECKING THE STOP LIGHT SWITCH CIRCUIT
Battery
7Tco
A
9%6
I-
(GO) :
To stop light
NOTENC: ON at all timesNO: OFF at all times
Description of operation
When the brake pedal is depressed during
con-
stant-speed travel, the stop light switch’s (NC
)
contacts for the cruise-control system open, with
the result that the current to the electromagnetic
clutch of the actuator is interrupted, thus
cancell-
ing the constant-speed travel.
At the same time, moreover, the closing of the (NO) contacts for the stop light results in the
Troubleshooting hint sending of the cancel signal to the control unit, so
that the actuator’s electromagnetic clutch current is discontinued within the control unit, thereby
canceling the constant-speed travel.
The flow of current is from the battery to fuse N O.
(15) of the junction block, the stop light switch.
and the control unit.
Diagnostic-No.16 (automatically cancelled)
ECU terminal voltage
Terminal
No
.
SignalConditions
3Stop light switch (load
When the brake pedal is depressed
side)
When the brake pedal is not depressed
11Stop light switch (pow-At all times
, er supply side)
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Termianl voltage 12v
ov
12v

13-346AUTO-CRUISE CONTROL SYSTEM - Troubleshooting6-2.
CHECKING THE PARK/NEUTRAL POSITION SWITCH CIRCUIT
ECU
-I
J
(12)
2mi
Park/neutral
position
switch
zc:
1
&
A
I
3pry
iz,:
T
3qpIII
1 ? 3;m456
/I
Starter motor
to the control unit, park/neutral position switch,
starter motor, and to ground; the cancel signal is
therefore input to the control unit, thus canceling
the constant-speed travel.
Description of operation
The park/neutral position switch also functions as
the switch for the starter.
If the selector handle is moved to the “N” posi-
tion during constant-speed travel, current flows
Troubleshooting hint
Diagnostic-No.16 (automatically cancelled)
ECU terminal voltage
Terra’Signal
2Park/neutral position switch At all times
ConditionsTerminal voltage
12v
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AUTO-CRUISE CONTROL SYSTEM - Troubleshooting13-347
6-3. CHECKING THE CLUTCH PEDAL POSITION SWITCH CIRCUIT
Ignition
switch
Junction block
ECU
NOTENO: OFF at all time
Description of operation If the clutch pedal is depressed during constant-
speed travel, the contacts of the clutch pedal position switch close, with the result that the
cancel signal is sent to the control unit, so that
the current to the electromagnetic clutch of
Troubleshooting hint
Diagnostic-No.16 (automatically cancelled)
ECU temrinal voltage the actuator is discontinued within the control
unit, thereby canceling the constant-speed travel.
The flow of current is to the ignition switch (IGI),
fuse No. (9) of the junction block, the
clutch pedal position switch, and the control unit.
/ Te;z,nal 1Conditions Terminal voltage
Clutch pedal position
switch When the clutch pedal is depressed
When the clutch pedal is not depressed12v
ov
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