display MITSUBISHI 3000GT 1991 Workshop Manual

SERVICE BRAKES -Anti-lock Braking System Troubleshooting
1 CONTINUED FROM PREVIOUS PAGE 1
IAfter a test drive, use self diagnosis to
check (Refer to
P.35-29.).
INo trouble codes output and normal
codes are displayed?NoNo diagnosis output
NoTrouble codes are output
Yes
All ABS functions are normal.
(Nor are there stored memory of
past trouble code.)
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[Explanation][Hint]
The ABS ECU detects breaks in the wheel speedIn addition to a broken wire/short circuit in the wheel
sensor wire. This trouble code is output if the wheelspeed sensor, also check whether the sensor gap is
speed sensor signal is not input (or short circuited)too large, sensor harness wire is broken, or sensor
or if its output is low when starting to drive or whileharness and body connector are not properly con-
driving.
netted.E-2 When diagnosis code“15 VEH. SPD. SNSR.” is displayed
[Explanation]l Broken sensor harness
This trouble code is output when there is anl Poor connection of connector
abnormality (other than broken wire or short circuit)
NOTEin any of the wheel speed sensor output signals
(1) If contact is poor, check the sensor cable by
while driving.bending and lightly stretching it.
[Hint](2) Except for the case where a fault condition
The following can be considered as the cause of theexists in the system, but the inspection results
wheel speed sensor output abnormality.are normal; if an abnormality cannot be found in
l Distortion of rotor, teeth missingthe sensor. circuit displayed as abnormal, erase
lLow frequency noise interference when sensorthe diagnosis code and turn the ignition switch
harness wire is brokento OFF once, and then test-drive again.
l Noise interference in sensor signalIf the same trouble code is output, replace the
lSensor output signal is below the standard valueABS ECU. If the trouble does not occur any-or amplitude modulation is over the standardmore, the problem is likely to be with the ABS
ECIJ.\value. Using an oscilloscope to measure the
wave shape of the wheel speed sensor output
signal is very effective.
I\-- -.(If the trouble is in the speed sensor circuit, butdis difficult to recreate, it will recur even after the
ABS ECU has been replaced.)35-38
SERVICE BRAKES -Anti-lock Braking System Troubleshooting
E-lWhen the following diagnosis codes are displayed “11 FR SNSR. OPEN”
“12 FL SNSR. OPEN” “13 RR SNSR. OPEN” “14
RL SNSR. OPEN”
d
SPEED SENSOR
FRONTCLH) FRONTGWR!%R(LH) REARmi
m I@m @
If?All110130125ASS-ECI.+tB5
8
8I
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35-40SERVICE BRAKES -Anti-lock Braking System Troubleshooting
E-3When diagnosis code “21 G SNSR.” is displayed
[Explanation]
The ABS-ECU outputs this trouble code in the
following cases.
l G sensor OFF trouble (It is judged that the G
sensor continues to be OFF for more than
approximately 13 seconds except when thevehicle is stopped or when there is stop light
switch input.)
lWhen there is a broken wire or short circuit in
the harness for the G sensor system.
FUSIBLE LINK@
4
pilGGRq;
I4
Bd
pEmg=1
--a
2
__1
It
I,1II1 Ii II II II Ii II II I/ II ;/ II II II II !: II//IIII/.--A
X35-LK-R9505
I
IiNo IfIs G sensor normal? (Refer
to
P.35-92.)Replace G sensor.
I
Yes
Remove the ABS-ECU
connector and check at
the harness connector.
With the ignition key “ON”,
does the voltage between
terminal No. 6 and groundindicate battery voltage?
Repair harness.
”
ABS-ECU malfunctionIJP Replace ABS-ECU.
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SERVICE BRAKES -Anti-lock Braking System Troubleshooting35-41E-4 When diagnosis code“22 STOP LAMP SW” is displayed
ii’ [Explanation][Hint]
The ABS-ECU outputs this trouble code in theIf the stop light operates normal, the harness for the
following cases.stop light switch input circuit is broken or there is a
lStop light switch remains on for more than 15malfunction in the ABS-ECU.
minutes while the ABS is not functioning.
lThe harness wire for the stop light switch may
be open.
L
FUSIBLE,LINK@
J/B
0
I
I
ABS-ECU29
j 1 ) 2 13 14) 5 / 6 17 / 9 j 9 ~10~11~12~13(14~15(161171~9~~'9~0l21~2~3l9~~~6~~~9~~0l31l321U13l35l
KX35-AK-33306
F Check the stop light related
go out
normally?circuit and repair problem
spots.
When the brake pedal is pressed
between connector terminal No.
29 and ground indicate battery
I1 voltage! , Yes /Repair harness.
Is the voltage between No.
1terminal and ground equal to the
battery voltage when measured
wrth resistor connector discon-
nected?
YesRepair harness.
6NoIs resistor resistance 780 to
860 sl?) Replace resistor.
YesIs there continuity between No. 2
FpylReplace ABS-ECU.
visionI

35-42SERVICE BRAKES -Anti-lock Braking System Troubleshooting
E-5When diagnosis codes “41 FR SOL. VALVE”,
“42 FL SOL. VALVE” or “43 VALVE DRIFT”
are displayed.
‘LJ[Explanation]
The ABS-ECU normally monitors the solenoid valve
drive circuit.
If no current flows in the solenoid even if the ECU
turns the solenoid ON or if it continues to flow even
when turned OFF, the ECU determines thesolenoid coil wire is broken/short-circuited or the
harness is broken/short-circuited, and then these
trouble codes are output.
ABS-ECU controls the solenoid valve current and if
the current value of the solenoid valves differs from
j:
z!d
9
E6T
mA9f#;NATIOM
I-N----_---____IGNITION
SWITCH(IG2)Fw
"50
fm!EaqG-R
?,I G-RI
X35-AK-K3507each other in the same mode, solenoid valve drift
error is produced and the ABS-ECU goes into the
failsafe mode.
1No
In the resistance value forthe solenoid valve withinthe range of the standard
values?
Standard value: 1.1 - 1.3 R
Yes
”
) Replace HU.
Connect HU 1 OP connector,
\ ci;;;;;;;t EC,U connector,)
Yes
+The harness wire for the
solenoid valve circuit
whose resistance value is
outside the range of the
standard value is brokenor short circuited.
Repair harness.
1 Malfunction of ABS-ECU4 Replace ABS-ECU.I IIII1
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SERVICE. BRAKES -Anti-lock Braking System Troubleshooting35-43
E-6When diagnosis code “51 VALVE RELAY” is displayed
I
L[Explanation]
When the ignition switch is turned ON, the ABS
normal. In addition, normally it monitors whether or
ECU switches the valve relay OFF and ON for annot there is power in the valve power monitor line
initial check, compares the voltage of the signal tosince the valve relay is normally ON. If the supply of
the valve relay and valve power monitor line voltagepower to the valve power monitor line is inter-
to check whether the valve relay operation is
rupted, this trouble code will be output.
b
L
IGNlTIONSWITCH(IG1)
-I--
iz
=pi7TEaq
dI
6
7
Ed
COMBINATION
METER
--;Gm1 I 11
I /I
--- --
710 4Ii+
mI%
~d10 2
--- -- -?
ii3Dz62 27
iE b
1112j31a15(6/71618/10(11112113/14/15j16/17(18118~20~21~2~3~4~5~~~2@~~~0~31~2~3~~~35
KX35-AK-K3503
r-TSB I
( ;;reove;d ch; the>
4.IWhen the valve relay is checked,
are the following conditions
found?
No. 85
- No. 86: Resrstance
value 60 - 120 IINo. 30-No. 87a: Continuity
No. 30 - No. 87: No continuity
When batterv voltaoe IS aooliedbetween terminalsho. 86 and
No. 85.
No. 30
- No. 87: Contrnurty
No. 30 - No. 87a: No continurtyNo
I1-----+Valve relay malfunction
+l
IReplace valve relay.I
Yes
&I/ No1IWith the ignition key “ON”,
does the voltage between the
connector terminal No. 52 and
ground indicate battery voltage?
Yes
Connect the HU harness and
\ remove the ECU connector.
+II NnrIground Indicate battery voltage.
Replace ABS
ECIJ.
vision

35-44SERVICE BRAKES -Anti-lock Braking System Troubleshooting
E-7When diagnosis code “52 MOTOR RELAY” is displayed
[Explanation]
The ABS ECU outputs this trouble code for the
motor relay and motor in the following cases.
l When the motor relay does not function
lWhen there is trouble with the motor itself and it
does not revolve
lWhen the motor ground is disconnected and the
motor does not revolve
l When the motor continues to revolve
[Hint]
If there is motor operation noise during MUT forced
drive mode, there is a broken or short circuited
motor monitor wire.
FUSIBLE LINKa
=
::
s* m’ IL% Q7
plGizq”+-103 1
----..-___I _-
3%ECU2526L--h h
Th v-sTIII
14 ’
+---I
i”
’-ll21314 15 16 17 16 ~8~10)11~12~13~14~15~16~17~16~li1Q~0~1~~23~4~*6~2?~E~Q~30~1~2~33~~~5J
X35-AK-R3500during MUT forced drive mode?
Remove the motor relay.
I
1 ;;pa4r&&rness between 1
5Remove the motor relay and
check resistance values.
No. 85
- No. 86: Resistance
value 30 - 60 fiNo. 30 - No. 87: No continuity
Battery voltage is applied
kotw8esfn terminals No. 85 and
No. 30
- No. 87: ContinuityReplace motor relay.
1Yes
L
+I, NoIIIs pump motor ground connected
normally?Connect ground wire.
I
YesInstall motor relay and remove
HU connector.
@Vyiground indicate battery voltage?
I Yes
IConnect the HU connector
and remove the ECU connectorRepair harness.
J- No
Is resistance between bodyP Malfunction of harness
connector terminal No. 2
Lrbetween HU and ECU
and No. 26 30 - 60 a?
ItNc-11 I<
r 1 Repair harness.;~~:;$$a$?%dABS ECU malfunction
> Replace ABS ECU.
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SERVICE BRAKES- Service Adiustment Procedures35-59
iPressure decrease
Release
pjgKq LockDrag force when
pedal is releasedMUT actuator
itest start
3 sec.
I3 sec.
Pedal operation
Pedal operation
pattern @
pattern @
JJ.r__---------------
I
I
I
I----------
------------------4
I1r-’ - - - - - - - - - a -I6 sec.
1------ __---____-__ - --___-__--_ ---J’-
14FOO96(7) If any abnormality is found in the check, take corrective
action according to the following “Judgement in Inspection
by Feel” table.
Judgement in Inspection by Feel
No.
I IMUT display
04FR VALVE
M
05FL VALVEM
t
106”
I IRear VALVEM”Operation
(1) Depress brake pedal to
lock wheel.
(2) Using the MUT. select
the wheel to be checked
and force the actu-
ator to operate.
(3)Turn the selected wheel
manually to check the
change of brake force.
1-1 ‘gkte / Remedy
Normal
Brake force
released for 6
seconds after
locking.Wheel doesClogged brake Check and
not lock when
line other than clean brake
brake pedal HUline
is depressed.
Clogged
hy-Replace HU
draulic circuit assembly
in HUBrake force is
Incorrect HUConnect
not releasedbrake tubecorrectly
connection
HU solenoid
valve not
functioning
correctlyReplace HU
assembly
NOTE*: FWD
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c
LJ
SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - General information52B-3
ONSTRUCTION DIAGRAM
Right front Impact sensor
/Left front impact
sensor
SRS diagnosis
unit(Incorporated safing
impact sensor)19FO138‘EHICLE
1~ENTIFICATION:ODE CHART
‘LATEmodulelQFO118
NOTEThis construction diagram displays the general view of the SRS components.
For details, refer to “SRS Schematic”
(P.52B-6). “Configuration Diagrams” (P.52B-7) and “SRS Circuit Diagram”(P.52B-11).
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52B-18 SUPPLEMENTAL RESTRAINT SYSTEM (SRS) - Troubleshooting
DIAGNOSTIC SEQUENCE
TEST 1SRS WARNING LIGHT DOES NOT EXTINGUISH
\1 I
Vehicle Model Selection
{
F
1. SELF-DIAG CODE2. SERVICE DATA
3. ACTUATOR TEST
4. SPECIAL TEST
,, I,
0
“CLEAR” and“4”1.
SIMLTD VEH SPD
2. PULSE CHK
3. DRIVE RECORDER4. EXTERNAL COMM
” 1 ”
1’1
y,,
SRS-AIR BAGID NO.: 19INPUTABOVE CODE
I(1) Turn the ignition key to the “ON” position.
(2) The Multi-use Tester display section successfully passes
the self-check and the model selection menu is displayed
after completing the self-check of the Multi-use Tester.
Select 3000GT 91 MDL [No. 3 (Non-Turbo) or No. 4 (Turbo)]
and SRS-AIR BAG system by entering the “YES” key.
(3) If the Multi-use Tester displays “CAN’T COMM.“, check
the Multi-use Tester and vehicle side self-check diagnosis
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page.) and perform
[I.If the 3000GT 91 MDL SRS-AIR BAG system selection is
successful, continue with following steps.
(4) Select the “1. SELF-DIAG CODE” function and read (and
write down) all displayed diagnosis codes.
(5) Press the “CLEAR” key to return to the Function Selection
and select the
“4. SPECIAL TEST”.
(6) Pr+FE,the ”
1 ” key and select the “5. ERASE DIAG.
(7) Erase the diagnosis codes following the Multi-use Tester
messages.
(8) Start engine.
Does “SRS” warning light illuminate for about 7 seconds,
turn OFF and then remain extinguished for at least 45
seconds?
If yes, SRS system is functioning properly now.
If no, check the diagnosis codes written down at step (4)
above, refer to SELF-DIAGNOSIS QUICK REFERENCE
CHART
(P.52B-20) and perform service indicated there.