ignition MITSUBISHI 3000GT 1991 Service Manual

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.
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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-
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-_307a
-
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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

SERVICE BRAKES -Anti-lock Braking System Troubleshooting
35-35
IGNITIONSWITCH(IG2)
R&RRELAY
DIODE
KX35-AK-R35028PREVIOUS PAGE
With the ignition key in the
“ON” position, does voltage
between ECU connector
terminal No. 18 and ground
indicate the battery voltage?
Is there continuity between
body harness terminals No. 9
and No. 34, and ground?
Repair harness.
vNoIs there continuity between-body harness connector ter-diagnosis inspection
minals No. 23 and No. 24,terminal and ABS ECU
and diagnosis inspection ter-
minals No. 4 & No. 1 O?Yes
”Malfunction of ABS ECU
Replace ABS ECU.
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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.
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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
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2
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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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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%
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--- -- -?
ii3Dz62 27
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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

37A-10STEERING - Service Adjustment Procedures
BLEEDINGM37FKAl
1.Jack up the front wheels and support them by using a floor
stand.
2. Manually turn the oil pump pulley a few times.
3. Turn the steering wheel all the way to the left and to the
right several times.
4. Disconnect the high-tension cable, and then, while operat-
ing the starting motor intermittently, turn the steering
wheel all the way to the left and right several times (for 15
to 20 seconds).
Caution1. During air bleeding, replenish the fluid supply so
that the level never falls below the lower position ofthe filter.
2. If air bleeding is done while engine is running, the
air will be broken up and absorbed into the fluid; besure to do the bleeding only while cranking.
5. Connect the ignition cable, and then start the engine
(idling).
6.Turn the steering wheel to the left and right until there are
no air bubbles in the oil reservoir.
7.Confirm that the fluid is not milky, and that the level is up to
the specified position on the level gauge.
8. Confirm that there is very little change in the fluid level
when the steering wheel is turned left and right.
Fluid level change:wlthln 5 mm 1.2 in.)I
9.Check whether or not the change in the fluid level is within
5 mm
(.2 in.) when the engine is stopped and when it is
Irunning.
Caution
While enginerunningWhile enginestopped13UOl1. If the change of the fluid level is 5 mm
I.2 in.) or
more, the air has not been completely bled from thesystem, and thus must be bled completely.
2. If the fluid level rises suddenly after the engine is
stopped, the air has not been completely bled.
3. If air bleeding is not complete, there will be
abnormal noises from the pump and the flow-
control valve, and this condition could cause a
lessening of the life of the pump, etc.
LJ
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