1991 MITSUBISHI 3000GT clutch

13-160CRUISE CONTROL SYSTEM - Troubleshooting
NOTECruise control system cannot be set.This chart contains troubleshooting procedures to
perform when a problem cannot be detected by
self diagnosis.
Check input. (Refer to P. 13-l 73.)
I
Yes
Is the result of input check O.K.?
!
b Check vacuum pump assembly circuit.(Refer to P. 13-l 67.)
NoNOTEIf the results of checks on the vacuum pumpassemblv circuit and actuator parts (refer to P.13-184.)indicate that they are good, replace the control unit
pen
circurt In contraeplace controlswitch
Defective clutch switchReplace clutch switch
Even when select lever isplacedin
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CRUISE CONTROL SYSTEM - Troubleshootina13461
Trouble symptom
l The set vehicle speed variesgreatly upward or downward.l “Hunching” (repeated alter-
nating acceleration and
deceleration) occurs after
setting is made.
Probable cause
Check chart No.Remedy
Malfunction of the vehicleNo. 4Repair the vehicle speedspeed sensor circuit
sensor system, or replacethe part.Malfunction of thespeedometer cable orspeedometer drive gear
Vacuum pump assembly
No. 5Repair the actuatorcircuit poor contact
system, or replace thepart.Malfunction of thevacuum pump assembly
(including air leaks from
negative pressure
passage)
The cruise control system is notcanceled when the brake pedal
is depressed.Malfunction of the ECU
-Replace the ECU.
Brake switch (for cruiseNo. 6Repair the harness or
control) malfunction
replace the stop light
(short-circuit)switch.
Vacuum pump assemblyNo. 5Repair the harness ordrive circuit short-circuitreplace the vacuum pump
assembly.
The cruise control system is notcanceled when the clutch pedalis depressed. (It is canceled, however, whenthe brake pedal is depressed.)Malfunction of the ECU
-Replace the ECU.
Damaged or disconnected
If the input checkRepair the harness, orwiring of clutch switchcode No. 26 indicatesrepair or replace the clutch
input circuita malfunction.switch.No. 7Clutch switch improper
installation (won’t switch
ON)
Malfunction of the ECU-Replace the ECU.
The cruise control system is notDamaged or disconnectedIf the input checkRepair the harness, or
canceled when the shift lever iswiring of inhibitor switchcode No. 26 indicatesrepair or replace themoved to the “N” position.
input circuita malfunction.inhibitor switch.
(It is canceled, however, when
No. 8
the brake pedal is depressed.)Improper adjustment of
inhibitor switch
Cannot decelerate by using the
SET switch.Malfunction of the ECU
Temporary damaged ordisconnected wiring of
control switch input
circuit
-
No. 2Replace the ECU.
Repair the harness orreplace the control switch
Vacuum pump assemblyNo. 5Repair the harness orcircuit poor contactreplace the vacuum puml:assembly.
Malfunction of thevacuum pump assembly
Malfunction of the ECU
-Replace the ECU.
NOTEECU: Electronic control unit
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13-162CRUISE CONTROL SYSTEM - Troubleshooting
Trouble symptomProbable causeCheck chart No.
Remedy
Cannot accelerate or resume speedOpen or short circuit in
No. 2by using the RESUME switch.RESUME switch circuit inReplace the control switch
control switch
Vacuum pump assemblyNo. 5circuit poor contactRepair the harness or
replace the vacuum pump
Malfunction of thevacuum pump assembly
(including air leaks
from negative pressurepassage)assembly.
Malfunction of the ECU-Replace the ECU.
Even when CANCEL switch is set toON, cruise control is not canceled
Open or short circuit
in CANCEL switchIf the input check
Replace the control switch
(Cruise control, however, iscode No. 27 indicatescircuit in control switch
canceled when brake pedal isa malfunction.
depressed.)No. 2
Malfunction of the ECU-Replace the ECU
The cruise control system can be set
Malfunction of theNo. 4while traveling at a vehicle speedvehicle-speed sensorRepair the vehicle speed
of less than 40 km/h (25 mph), or
circuitsensor system, or replace
there is no automatic cancellationthe part.
at that speed.Malfunction of thespeedometer cable orthe speedometer drive
gear
Malfunction of the ECU
-Replace the ECU.
The cruise control indicator light
No. 3
of the combination meter does notDamaged or disconnectedbulb of indicator lightRepair the harness or
illuminate. (But cruise controlreplace the light bulb.
system is normal)Harness damaged or
disconnected
Malfunction of the ECU
-Replace the ECU.
Cruise control ON indicator light
No. 3
does not come on. (However, cruiseBurned-out indicator lightbulbRepair the harness or
control is functional.)replace the main switch.
Open or short circuit in
harness
Malfunction of control functionby
ON/OFF switching of ELC 4 AA
accelerator switch.
(Non-operation of damper clutch,
2nd gear hold, etc.)
Overdrive is not canceled during
fixed speed driving
No shift to overdrive during
manual driving.
Malfunction of circuitrelated to acceleratorswitch OFF function
Malfunction of the ECU
Malfunction of circuit
related to overdrive
cancellation, or mal-
function of ECU
No. IO
No. 11Repair the harness or
replace the part.
Repair the harness or
replace the part.
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13-168CRUISE CONTROL SYSTEM - Troubleshooting,I
I 6 IInspection of stop light switch circuitIIIII
FUSIBLE LINK@
IDESCRIPTION OF OPERATIONIJ iWhen the brake pedal is depressed during vehicle
speed control, the cruise control (NC) contact of the
stop light switch is opened to interrupt the power
supply to the vacuum pump assembly for
cancella-tion of vehicle speed control. (Refer to P. 13-I 67.) At
the same time, the stop light (NO) contact is closed.
As a result, a cancel signal is input to the control unit
which internally interrupts the vacuum pump
assembly drive circuit.
TROUBLESHOOTING HINTSECU terminal voltage
Terminal
No.Signal nameConditionTerminal
voltage
15Stop light
switchWhen brake pedal
is depressedSystem
voltage
When brake pedal
is not depressed
OVh
”z15d
El 1’STOP
LIGHT
xx35-AX-R1305
7Inspection of clutch switch circuit
CRUISEc!$;ROLDESCRIPTION OF OPERATIONWhen the clutch pedal is depressed during vehicle
speed control, the contact of the clutch switch is
closed. As a result, a cancel signal is input to the
control unit which internally interrupts the power
supply to the vacuum pump assembly drive circuit
for cancellation of vehicle speed control.
TROUBLESHOOTING HINTSECU terminal voltage
II,Terminal
Signal nameConditionTerminal
No.voltage
1Clutch switchWhen clutch pedalOVis depressed
When clutch pedal System ,
is not depressedvoltage
d
KK35-AK-R130TA
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CRUISE CONTROL SYSTEM - Troubleshooting
INPUT CHECK TABLE
odeDisplay patterns (output codes)Input operationCheck results40.(use with voltmeter)
21SET switch ONSET switch circuit normal
n
22RESUME switch.ONRESUME switch normal
23
nn
Stop light switch ON(brake pedal depressed)
Stop light switch circuit normal
24Vehicle speed more than approx.
40 km/h (25 mph)Vehicle speed sensor circuitnormal if code Nos. 24 and 25
are displayed
25Vehicle speed less than approx.
40 km/h (25 mph)
26M/T
Clutch switch ON
-1~ ~~;~~o~~i~~~~;sed’
(SELECT lever placedin “N” position)Clutch switch circuit normal
Inhibitor switch circuit normal
27CANCEL switch ONCANCEL switch circuit normal
TPS output voltage 1.5 V or more
Throttle position sensor circuit
(Accelerator pedal depressed more normal
than half the way)
Idle switch OFF (Accelerator pedalIdle switch circuit normal
depressed)@ Set main switch to OFF.
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CRUISE CONTROL .SYSTEM - Troubleshooting13-177
DASH PANELJunction block
JUNCTION BLOCKFront side
36FOOO236FOOO3
i
10 Clutch pedal switch 11 Stop light switch
12 Clock spring
13 Accelerator pedal switch
LOCATION OF CONTROL UNIT
E%sQ/I.LIlll-I BCrutse
!tcontrol
unit
GROUND POINT14 Over drive switch
15 Cruise control unit16
l 7
1
Front wiring harness and junctionl 8 block combination
19 Adapter wiring harness and junction block
combination
Body wiring harness
(LH) and junction block
I-\ --*
I d
4tT
-G
1
q\ ($$ 16F02E
36FOO18
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13-180CRUISE CONTROL SYSTEM - Service Adjustment Procedures.
4
ET: ON
07FOOl;Control switch
\E: ON
t
07FOOliControl switch
\
SET: ON
07FOOlControl switch
\
07FOOl
CRUISE CONTROL SETTING CHECK(1) Switch ON the main switch.
(2) Drive at the desired speed within the range of approximate-
ly 40
- 145 km/h (25 - 90 mph).
(3) Operate the control switch downward. (SET switch: ON)
(4) Check to be sure that the speed is the desired constant
speed when the switch is released, and also check to be
sure that the CRUISE indicator light (within the combination
meter) illuminates.
NOTEIf the vehicle speed decreases to approximately 15 km/h (9
mph) below the set speed, because of climbing a hill for
example, the cruise control will be cancelled.
SPEED-INCREASE SETTING CHECK(1) Set to the desired speed.
(2) Operate the control switch upward. (RESUME switch: ON)
(3) Check to be sure that acceleration continues while the
switch is hold, and that when it is released the constant.
speed at the time when it was released becomes the
driving speed.
NOTEEven if, during acceleration, the vehicle speed reaches or
exceeds the high limit [approximately 145 km/h (90 mph)],
acceleration will continue, however, when the switch is
released, the set speed (“memorized speed”) will become
the high limit of the vehicle speed.
SPEED REDUCTION SETTING CHECK(1) Set to the desired speed.
(2) Operate the control switch downward. (SET switch: ON)
(3) Check to be sure that deceleration continues while the
switch is held, and that when it is released the constant
speed at the time when it was released becomes the
driving speed.
NOTEWhen the vehicle speed reaches the low limit [approx-
imately 40 km/h (25 mph)] during deceleration, the cruise
control will be cancelled.
CRUISE CONTROL CANCELLATION AND SET SPEED RE-
SUME CHECK(1) Set cruise control.
(2) In the cruising condition of the cruise control mode, check
that when any of the following operations are performed,
the normal drive mode is restored and
,the vehicle coasts
smoothly.@ Move the control switch toward you. (CANCEL switch:@ Depress the brake pedal.@ Depress the clutch pedal.
@ Place the gear selector lever in the N range.

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CRUISE CONTROL SYSTEM - Service Adjustment Procedures13-183
onoo5J16LO285
141014;
TFA0359
16FO13LResistance
3--1Okl2
STOP LIGHT SWITCH/BRAKE SWITCH INSPECTION(1) Disconnect the connector.
(2) Check for continuity between the terminals of the switch.
O-O: Continuity
Brake switchStop light switch
1423
Whenbrakepedal00depressed.
When
brake
pedal00not depressed.CLUTCH SWITCH INSPECTION
(I) Disconnect the connector.
(2) Check that there is continuity between the terminals when
the clutch pedal is depressed, and that there is no
continuity when the pedal is released.
INHIBITOR SWITCH (“N” POSITION) INSPECTION
(1) Disconnect the connector.
(2) Check to be sure that there is continuity between connec-
tor terminals
@and @when the shift lever is moved to the
“N” range.
VEHICLES SPEED SENSOR INSPECTION
Use circuit tester to check circuit repeats off/on between
terminals when speedometer shaft turned several times.

(1) Remove the vehicle’s speed sensor and connect as shown
in the illustration, using a 3
- 10 kQ resistance.
(2) Use a voltmeter to check for voltage at terminals @ and @
when the pulse generator shaft is turning. (One revolution
is four pulses.)
16R0273
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