1991 MITSUBISHI 3000GT warning light

SERVICE BRAKES -Anti-lock Braking System Troubleshooting35-33
1i, 1 CheckABSECU. ,
Remove the ECU connector and
check.Does the voltage between ECU harness
> Broken wire between ABSj Repair harness.
connector terminal No. 25 and ground
warning light and ECU
indicate battery voltage while the
ignition key is in the “ON” position?
Yes
> ABS ECU malfunction> Replace ABS ECU.
Remove valve relay and check.
I
1Nois valve relay normal? (Refer to
P.35-62.)) Valve relay malfunction+ Replace valve relay.IYes
Install the valve relay, remove the HU
connector and check.
Does voltage between the HU harness
uLEm-h[ Repair harness.
connector terminal No. 8 and ground
indicate battery voltage
while the
ignition key is in the “ON” position?
Yes
r7; t%$~?$!Je~~~g~undIIs there continuity between HU harness9 Repair harness.
connector terminal No. 9 and ground?
Is there continuity between HU harness
connector terminals No. 8 and No. 9?Yes+ HU malfunctionI+ Replace HU.
b Connector not connected
securely.- Replace connector.
1 TSB Revision

35-34SERVICE BRAKES -Anti-lock Braking System Troubleshooting
II1
1 B 1 ABS warning light stays on when the ignition key is in the “ON” position.1II\[Explanation]
[Hint]
k.JThis is the symptom when the ABS ECU does not
power up due to broken ECU power circuit, etc.,Check the diagnosis output and if there is no output
when the fail safe function operates and isolates thevoltage or if the MUT and ABS ECU cannot
system or when the warning light drive circuit iscommunicate, there is a good possibility that power
short circuited.is not flowing to the ECU.
IGNITIONSWITCH(IG1)Caution
lIf the trouble code is output, the system can
be in the fail safe mode. In such a case, erase
the trouble code and then restart the engine
to check if the system is currently in a fault
condition.
f
j @
?
j 0
:ml-
I2a-----11 g:I aI7
:I1
-_307a
-
I-=_-. -----------1
P
Y
4 a:&
I25ABS
ECU
iz- 11213 ia1516j7j819~10~11~12~13~14~15~16~17~1819l20l21C2C3Ca~25~~7~3~29~0~1~32~3~35
:95-AK-R9502
4
Replace ECU.
I YesI.
Replace HU or replace
valve relay.
I
_
ai.. .
ITSB hevIsIon

35-36\
SERVICE BRAKES -‘\Anti-lock Braking System Troubleshooting
CABS warning light does not illuminate when the ignition key is in the “START” position.
[Explanation]
The ABS ECU uses the
IG2 power source which is
turned off in the “START” position. The ABS
warning light uses the
IG, power source which is
not turned off even in the “START” position.
Consequently, in the “START” position, power is off
LJand the ECU turns the valve relay OFF. If the
warning light does not illuminate at this time, there
is trouble in the warning light circuit on the valve
relay side.
EfiE-
9B
wIGNSW1--
J/BF
COMBINATIONMETER
G-R 11 G-
IN;IGl)
ITSB IRemove the hydraulic
unit (HU) connector andcheck.
Yes
c-No -Is there continuity between-> Broken line between HUbody connector terminal No. 9
and body ground
and ground?
-No 7Is there continuity between> Valve relay malfunction orHU connector terminal No. 8
break in HU harness wire
and terminal No. 9?
YesYes
&
Replace valve relay.I
1
HU harness malfunctionj Replace HU.
NOTEWhen performing the check marked *, note polarity of the diode
(refer to the circuit diagram).
visionI

SERVICE BRAKES -Anti-lock Braking System Troubleshooting35-37
DABS warning light blinks once after the ignition key is turned to the “ON” position. It
Lilluminates in the “START” position and blinks once again when turned to the “ON” position.
[Explanation]
1 sec. while itharness between the ECU and the warning light, the
light illuminates only when the valve relay is off in
performs a valve relay test. If there is a break in the
the valve relay test, etc.
IGNITIONSWITCH(IG1)I
J/B
F
2
r+im
md
/
L/
COMBINATION
METER
ABS-ECU-____
KK35-KK-It3503In the ignition key “ON”
position, does voltage
between terminal No. 25 and
ground indicate battery
voltage?ABS warninglight and
Yes
Repair harness.
vMalfunction of ABS ECU
+ Replace ABS ECU.
TSB Revision

35-58SERVICE BRAKES - Service Adjustment Procedures
POINTS IN WAVEFORM MEASUREMENT
Symptom
Too small or zero waveform
amplitudeProbable causes
Faulty wheel speed sensorRemedy
Replace sensor
Incorrect pole piece-to-rotor clearance
Adjust clearance
Waveform amplitude fluctuates
excessively (this is no problem ifAxle hub eccentric or with large runout
Replace hub
the minimum amplitude is
100 mV
or more)
Noisy or disturbed waveformOpen circuit in sensor
Open circuit in harness
Incorrectly mounted wheel speed sensor
Rotor with missing or damaged teethReplace sensor
Correct harness
Mount correctly
Replace rotor
NOTEThe wheel speed sensor cable moves following motion of the front or rear suspension. Therefore, it is likely that it has an
open circuit only when driving on rough roads and it functions normally on ordinary roads. It is, therefore, recommended
to observe sensor output voltage waveform also under special conditions, such as rough road driving,
(ME!991 377)12FOO5i
INSPECTION OF HYDRAULIC UNITINSPECTION BY FEEL
(I) Jack up the vehicle and support the vehicle with rigid racks
placed at the specified jack-up points.
(2) Release the parking brake and determine the drag force
(drag torque) of each wheel by feel.
LJ(3) Set the MUT through the adapter harness (MB991377) as
illustrated.
(4) After confirming that the shift lever or selector lever is in
the neutral position, start the engine.
The ABS warning light lights up, it goes into the MUT mode.
In the MUT mode, ABS does not function.
(5) Operate the MUT to force the actuator to operate (item No.
04, 05, 06).
(6) Turning the wheel manually, check the change of the
braking force when the brake pedal is depressed.
The change should be as shown in the following illustration.
NOTEWhile the ABS is in the fail safe mode, the MUT actuator
test cannot be made.
TSB Revision

35-60SERVICE BRAKES - Service Adjustment Procedures
INSPECTION BY USING BRAKE FORCE TESTER
NOTE
(1) The brake force tester roller and tire must be dry during the
test.
(2) When testing the front brakes, apply the parking brake and
when testing the rear brakes, apply chocks to the front
wheels to lock them.
(I) Place the front or rear wheels on the brake force tester
roller.(2) Set the MUT through the adapter harness
(MB9913771 as
illustrated.
(3) After confirming that the shift lever or selector lever is in
the neutral position, start the engine.
(The ABS warning light lights up, it goes into the
-MUTmode. In the MUT mode, ABS does not function.)
(4) Operate the brake force tester roller.
(5) Depress the brake pedal until the brake force tester
indicates the following value and keep the brake force at
this level during the test.
Front wheels: 1,000 N (220
Ibs.)Rear wheels: 650 N (143
Ibs.)(6) Allow the brake tester indication to stabilize before operat-
ing the MUT to perform actuator test (Item No. 01,
02, 03).
Then, read change of tester indication.
Referring to the following “Judgement in Inspection by
Using Brake Force Tester” table, judge and take corrective
action if necessary.
NOTEWhile the ABS is in the fail safe mode, the MUT actuator
test cannot be made.
1 TSB Revision

When energized
Between terminals 4 and 5Continuity
When de-energized
Between terminals 4 and 5\i fl \\ 16FO264No continuity
Between terminals 1 and 3Continuity
16FO122L--J18FOCII
SERVICE BRAKES - Service Adjustment ProceduresI
INSPECTION OF POWER RELAYM35FOAP
7
1.Remove the relay box cover in the engine compartment and
remove the power relay.
2. Apply the battery voltage to the terminal @ and check for
‘L-J1
continuity between the following terminals when the
terminal @ is short-circuited to ground.
35-62
14FOOS14FOO8
l-TSB
1
REMEDY IN CASE OF DISCHARGED BATTERY
M35FOAQIf the engine is jump-started, because of a completely
discharged battery, the vehicle may suffer misfiring and fail to
start if an attempt is made to start without allowing the battery
to recover sufficiently. This is because the ABS consumes a
great deal of current for its self check. In such a case, allow the
battery to sufficiently charge or remove the ABS power relay in
the engine compartment to disable the ABS. Removing the
ABS causes the ABS warning light to light. After the battery is
charged sufficiently, install the power relay and restart the
engine to check that the ABS warning light goes out.
INSPECTION OF VALVE RELAY AND MOTOR
RELAY (ABS)M35FOAR1. Remove the splash shield
(FR) and remove the relay box
cover by inserting a screwdriver between the hydraulic unit
and cover to pry off the lock.
2.Remove the relays. The one closest to you (larger one) is
the motor relay and the one farthest from you (smaller one)
is the valve relay.
‘d~ i
wision

36-1
PARKING
BRAKES
CONTENTSM36AA-.
PARKINGBRAKE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .8SPECIAL TOOLS . .._.._.............................................
PARKING BRAKE LEVER AND PARKINGSPECIFICATIONS................................................
BRAKE CABLE*....................................................5General Specifications....................................
SERVICE ADJUSTMENT PROCEDURES4Lubricants....................................................................Parking Brake Lever Stroke Check4Sealants
andAdhesives....................................................Parking Brake Switch Check
............................4Service Specifications....................................
TROUBLESHOOTING........................................
i
SUPPLEMENTAL RESTRAINT SYSTEM (SRS)
(1)A Supplemental Restraint System (SRS), which uses a driver-side air bag, has been installed in the 3000GT.(2)The SRS includes the following components: impact sensors, SRS diagnosis unit: SRS warning light, air bagmodule, clock spring, interconnecting wiring. Other SRS-related components (that may have to be
removed/installed in connection with SRS service or maintenance) are indicated in the table of contents byan asterisk (*).
WARNING!(1)Improper service or maintenance of any component of the SRS, or any SRS-related component, can lead to
personal injury or death to service personnel (from inadvertent firing of the air bag) or to the driver (fromrendering the SRS inoperative).(2) Service or maintenance of any SRS component or SRS-related component must be performed only at an
authorized MITSUBISHI dealer.(3) MITSUBISHI dealer personnel must thoroughly review this manual, and especially its GROUP 52B
-Supplemental Restraint System (SRS), before beginning any service or maintenance of any component of theSRS or any SRS-related component.
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