MITSUBISHI 3000GT 1991 Service Manual

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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13-176CRUISE CONTROL SYSTEM - Troubleshooting
HARNESS AND COMPONENTS LAYOUT
ENGINE COMPARTMENT
01 Jumper connector
02 Vacuum pump
03 Throttle position sensor04 Inhibitor switch
05
VeTkFo;peed sensor
INSTRUMENT PANEL
AND FLOOR CONSOLE
Combination meter
Main switchEngine front view
03
36FOOO5Engine rear view
16FO175
36FOO17
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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-I 78CRUISE CONTROL SYSTEM - Service Adjustment ProceduresSERVICE
ADJUSTMENT PROCEDURESCRUISE CONTROL CABLES INSPECTION AND ADJUSTMENT
I
MlSFTCA
‘\J ~
Cruise control actuator
Cruise control assemblyAdjusting nut A
Link B
.
Adillstinn nr~+ R\Cruise control
cable
Adjusting nut C
Accelerator cable
Throttle valve-Link A
07N0004(1) Set the air conditioner, lights and other switches to OFF for
inspection at no load.
(2) Let the engine warm up until it runs at idle.
(3) Check that the idle speed is within the specified range.
(4) Stop the engine and set the ignition switch to OFF.
(5) Check that the accelerator cable, cruise control cable and
throttle cable are routed without sharp bends.
(6) Depress the accelerator pedal to check that the throttle
lever moves smoothly from the fully-closed to fully-opened
position.
(7) Check the free travel state of the inner cables of the
accelerator cable, cruise control cable and throttle cable.
(8) If the inner cables are too loose or have no free travel at all,
check using the following procedure.@ Remove the’ link protector.
@ Loosen the adjusting and lock nuts of the throttle lever
and intermediate links A, B and C to place the throttle
lever and intermediate links A, B and C in the free state.
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CRUISE CONTROL SYSTEM - Service Adjustment Procedures13-179Adjusting nut C
07NOOlELink Blever
07N0019Link
B07NOOlE
y,jj--ww ,03LO122
\\ \18FO2.2'@ Set the ignition switch to ON (do not start the engine).@ Rotate intermediate link C in the direction shown until it
is blocked by the stopper, turn down adjusting nut C in
the direction that the free travel of the inner cable is
reduced, and back off adjusting nut C the specified
number of turns just before intermediate link C begins
to move.
Amount adjusting nut C is to be backed off:
About l/2 turn [inner cable free travel0
- 1 mm (0 - .04 in.)]
About two turns [inner cable free
travel 2 to 3 mm
(.08 to .12 in.)]@ Secure the accelerator cable with the lock nut.@ Turn down adjusting nut B in the direction that the free
travel of the inner cable of the throttle cable is reduced.
At the position where the lever of intermediate link B is
brought into contact with intermediate. link C, back off
adjusting nut B the specified number of turns.
Amount adjusting nut B is to be backed off:
About one turn [inner cable free travel 1 to 2 mm
(.04 to .08 in.)]@ Secure the throttle cable with the lock nut.@ Secure the adjusting bolt of the surge tank.@ Turn down adjusting nut A in the direction that the free
travel of the inner cable of the cruise control cable is
reduced. At the position where the lever of intermedi-
ate link A is brought into contact with intermediate link
B, back off adjusting nut A the specified number of
turns.
Amount adjusting nut A is to be backed off:
About one turn [inner cable free travel 1 to 2 mm
(.04 to .08 in.)]@ Secure the cruise control cable with the lock nut.@ After adjustment, check to see that the end of the fixed
SAS is in contact with the stopper of the throttle lever.
CRUISE CONTROL SYSTEM INSPECTION
MlBFlDA
CRUISE CONTROL MAIN SWITCH CHECK
(1) Turn the ignition key to ON.
(2) Check to be sure that the CRUISE CONTROL ON indicator
light within the combination meter illuminates when the
main switch is switched ON.
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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 Procedures13-181
Control switch
07FOO17
\\ \18FO22;
07FOOlO6 1 4
ILL: Illumination light
I
07FOO13
(3) With the vehicle at a speed of more than about 40 km/h (25
mph), check that when the control switch is moved upward
(RESUME switch: ON), the vehicle resumes cruising at the
speed held before cancellation of the cruise control mode.
(4) In the cruise control mode, check that when the main
switch is set to OFF, the normal drive mode is restored and
the vehicle coasts smoothly.
INDIVIDUAL PARTS INSPECTION
M13FEA
CRUISE CONTROL MAIN SWITCH INSPECTION
(I) Remove the main switch together with the switch garnish.
(2) Remove the main switch from the switch garnish.
(3) Operate the main switch and check for continuity across
the individual terminals.
ILL 2 3 4 5
Press OFF.
Neutral positionPress ON.000A
0
NOTE(I 1O-O denotes continuity across the terminals.(2) ILL: Illumination light
(4) Connect a positive lead from the battery to terminal @ and
a negative lead from the battery to terminal @ and check
that battery voltage is available across terminal @ and the
ground during the period the ON side of the main switch is
pressed and during the period before the OFF side is
pressed thereafter.
Check that when the OFF side of the main switch is
pressed thereafter, the battery voltage available across
terminal @ and the ground is reduced to 0 V.
07FOOll
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13-182CRUISE CONTROL SYSTEM - Service Adjustment ProceduresI
CRUISE CONTROL SWITCH INSPECTION(1) Remove the air bag module using the following procedure.I07FOO12
07NOOl@ Remove the negative terminal of the battery and wait
for more than 30 seconds.
d
CautionThe capacitor in the SRS diagnosis unit retains
enough voltage to deploy the air bag for a given
period even after disconnection of the battery. If anoperation is performed during that given period,
unintended deployment of the air bag could result
and cause serious injury.@Remove the air bag module. To remove the clock spring
connector
(squib connector) from the air bag module,
force the lock outward and pry it with a plain screwdriv-
er as shown at left so that no undue force will be
exerted on the connector when it is removed.@ The removed air bag module should be stored in a
clean, dry, flat place with the pad side up.
(2) Disconnect the connector of the control switch and operate
the control switch to measure the resistance between the
individual terminals.
If the readings are as shown below, the control switch may
be considered good.
Switch operationResistance between-iJ
terminals
When switch is not operated
When switch is operated toward you
(CANCEL switch: ON)
When switch is operated upward
(RESUME switch: ON)
When switch is operated downward
(SET switch: ON)No continuity
Approx. 0
1RApprox. 820
1RApprox. 2,700
fi
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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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13-184CRUISE CONTROL SYSTEM - Service Adjustment Procedures
07AOO51
07A005t07A005i
THROlTLE POSITION SENSOR INSPECTIONFor inspection, refer to
P.13-65.
IDLE POSITION SWITCH INSPECTIONFor inspection, refer to
P.13-68.VACUUM PUMP INSPECTION
Inspection of Solenoid Valves (Control and Relief Valves)(1) Disconnect the connector of the vacuum pump assembly.
(2) Measure the resistance values across terminals @ and @
and across terminals @ and
0.Standard value: 50
- 60 R
(3) Check that when the battery voltage is applied across
terminals @ and @ and across terminals @ and
0, the
operating sounds of the solenoid valves are heard.
(4) If the solenoid valves are defective, replace the vacuum
pump assembly.
Inspection of Motor
(1) Disconnect the connector of the vacuum pump assembly.
(2) Check that when the battery voltage is applied across
terminals @ and
@, the motor operates.
ACTUATOR INSPECTION(1) Remove the actuator.
(2) Using a vacuum pump, apply a negative pressure to the
actuator to check that the holder portion moves more than
35 mm (1.4 in.). Retain the negative pressure in that state to
check that the holder portion does not change its position.
(3) After the actuator has been mounted, check and adjust the
cruise control cable. (Refer to
P.13-178.)
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