1989 MITSUBISHI GALANT warning

SERVICE BRAKES - Anti-lock Braking System Troubleshooting35-21
A ABS warning light does not light at all.
[Explanation]
When it does not light up at all, there is a strong
possibility that there is trouble with ABS warning
light or with power to the light.
[Hint]
If other warning lights do not light up either, fuse is
probably blown.
MAIN FUSIBLE
LINK @IGNITIONSWITCH (IG2)IGNITIONSWITCH (IGl)
Ea
1
0 U
, ,8--1I
CL
, VALVE
fI*I1 RELAY 1 Ii 1,
M
i 10
z 13-
--3z2-&
rc11_ 3
t”71
_----
a-II
2
dt II
zz
c:
35 126J.27ABS ECU
1
GND GND GNDv v v
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14A0085

35-22SERVICE BRAKES- Anti-lock Braking System Troubleshooting
- N

o
With the ignition key in the “ON” posi-
Check fuse No. 9. If it is
tion. do other warning lights illuminate?
* blown, correct the cause of
the blown fuse and thenreplace the fuse.
I
Yes
Turn the ignition switch OFF and check.
4II., III,
Is the ABS warning light normal? (CheckNo cABS warning light bulb Replace ABS warning
for burned bulb.)burned.* light bulb.
I
Yes
NoThe harness between the
combination meter from
* fuse No. 9 is broken.
1
Repair harness.I
Circuit in combination metercRepair or replace com-
is broken. bination meter.
Yes
Is there continuity between terminals No.NoMalfunction of combination Repair or replace combi-
;,d”,l” No. 17 on the combination meter -meter
nation meter
Yes
Are instrument panel wiring harness, _
Noc Connect connectors firmly.
engine compartment wiring harness,
body wiring harness and ABS wiring
harness connectors connected properly? (Check for pins pulled out or
bent, repair as needed.)
Yes
Broken wire in ECU, valve relay or both
drive circuits. Check and repair both
circuits.
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SERVICE BRAKES - Anti-lock Braking System Troubleshooting35-23
the ignition key in the
position, remove the ECU connector
Does the voltage between ECU harness
No r Broken wire between ABS .
connector terminal No.25
and ground
indicate battery voltage? warning light and ECU.Repair harness.
Yes Replace ABS ECU.
(Remove valve relay and check.
>
Valve relay malfunction Replace valve relay.I
Yes
/Install
the valve relay and,
\
ignition key in the “ON
”
remove the HU connector and
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Does voltage between the HU harnessNo * Broken harness wire be- -Repair harness.
connetor terminal No.8 and ground indi-
tween ABS warning lightIcate
battery voltage? and HU
I
I Yes
Is there continuity between HU harness
No - Broken harness wire be-Repair harness.
connector terminal No.9
and ground? tween HU and ground
I
‘- N
o
Is there continuity between terminals No.
8 and No. 9 on the HU side connector?
I
- Repair harness or replaceHU.
YesConnector connection mal-
function
NOTEWhen inspecting the parts marked with l ,take care to the diode polarity. (Refer to the circuit diagram on P.35-21.)

35-24
SERVICE BRAKES - Anti-lock Braking System Troubleshooting
B ABS warning light illuminated after the engine is started and remains o\
n.
[Explanation]
This is the symptom when the ABS ECU does not
power up due to broken ECU power circuit, etc.,
when the fail safe function operates and isolates the
system or when the warning light drive circuit is
short circuited.
[Hint]
Check the on-board diagnostic output and if there is
no output voltage or if the scan tool and ABS ECU
cannot communicate, there is a good possibilit
y
that power is not flowing to the ECU.
Caution
l If there is no output of diagnostic trouble
codes, there is a good possibility that the
fail safe is functioning.
J/B
IGNITION
%FH
z
&7
i
CD10A
728
Is there on-board diagnostic No )output? (Is there communi-cation with scan tool?) CONTINUE TONEXT PAGE
Yes
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Does the ABS warning light
remain illuminated
even
with the ECU connector dis-
connected?
YesNoShort in ECU transistor
1 Replace ECU.I

35-26SERVICE BRAKES - Anti-lock Braking System Troubleshooting
CABS warning light does not illuminate when ignition key is in “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 IGl power source which is
not turned off even in the “START” position
.
Consequently, in the “START” position, power is off and 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.
MAIN IGNITION
FUSIBLE
LINK @
1440677 Remove and inspect
10 pin connectors of
the hydraulic unit.
W
ith the ignition key in the
No
“ON” position, does voltage
c Harness wire between
HU and warning light is
between body connector broken.
terminal
No.8 and ground
indicate the battery voltage?
Yes
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Is there continuity between ,No
body connector termina
l
. Broken line between HU
No.9 and ground?
and body ground
Remove the valve relay. Is
Nothere continuity between Valve relay malfunction
terminal No. 87a and No. 30?
Replace valve relay. I
HU harness malfunction
IReplace HU.I

SERVICE BRAKES -Anti-lock Braking System Troubleshooting35-27
DABS warning light blinks once after the ignition key is turned to the “\
ON” yFsiti?r!. It
illuminates in the “START” position and blinks once again when tur\
ned to the “ONpostilon.
[Explanation]
When power flows, the ABS ECU turns on th
e
harness between the ECU and the warning light, the
warning light for approximately 1 sec. while it light illuminates only when the valve relay is off in
performs a valve relay test. If there is a break in thethe valve relay test, etc.
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-.14AO681
Remove hydraulic unit
connector and ABS-ECU
connector and inspect at
L---J
the ABS-ECU harness
side connector.
In the ignition key “ON” _ No c Harness wire between
position, does voltage
be-ABS warning light and
tween terminal No.25
and ECU is broken.
ground indicate battery
vol-tage? I III
Yes
Malfunction of ABS ECU Replace ABS ECU.

35-34SERVICE BRAKES - Anti-lock Braking System Troubleshooting
TROUBLESHOOTING (ABS-AWD)
Confirm condition in the following way and diagnose accordingly.
c
P
t:
1
-)oes
the ABS warning light illuminate as described
elow up to the time the engine starts?
1) When the ignition key is turned to the “ON”
position, the ABS warning light blinks four times
for approximately
1 second due to the ABS ECU
(as a self check of the valve relays is performed),
and goes out and stays out.
2) W
ith the ignition key in the “START” position,
power to the ABS ECU is interrupted and the ABS warning light remains lit because the valve
relay is OFF.
(3) When the ignition key is turned from the “START’ position to the “ON” position, the ABS warning
light blinks four times for approximately
1
second (during this time a recheck of the valve
relays is performed), and then goes out and
stays out.
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rimonUILEAED nxL GNL”Oyg@O@~ 2F
ABS
warnmg’l~ght66A0093
ABS warning
lightONI
OFF
Ignitionkey
ACC, LOCK
114AO594
YesCONTINUE TO NEXT PAGENo
1
No.Trouble condition
ABS warning light does not light up at all.
1
ABSwarning
light
Ignition
keyACC, ON
OFFLOCK 1
I
When the lgnltlon
key IS turned to the
“ON” position, it remains lighted.
ABS warnina
ON , l Short in ECU warning light drive circuit
l Malfunction of ECU
-“l-l- -III
ignitionkey
ACC. LO!?-14AO591
Major causes
l ABS warning light bulb is burnt out.
l Open in ABS warning light electrical circuit (check for blown fuse)
l Fail safe is functioning due to ECU on-
board diagnostic
Does not illuminate when ignition key is
in “START” position. l Malfunction of valve relay
l Break in harness between ABS warn-
ing light and HU
l Break in harness between HU and
14AO595
Remedy
Check, using flow
chart A (Refer to
P.35-39.)
Check, using flow
chart B (Refer toP.35-42.)
1 2 /light
-
Check, using flow
chart C (Refer to
P.35-44.)
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SERVICE BRAKES .- Anti-lock Braking System Troubleshooting35-35
No.
4
rBSvarningght
I!Jnitlonkey
L
Trouble condition
After the ignition key is turned to the “ON” position, it blinks once and then
illuminates when it is turned to the “START” position. When the key is
returned to the “ON” position, the light
blinks again. (Blinking with the ignition
key in the “ON” position is synchronized
with operation noise of the valve relay.)
14A0593
CONTINUED FROM PREVIOUS PAGE Major causes
l Break in harness for ECU warning light drive circuit
l Malfunction of ECU
when starting to drive the car? Does the ABS warning light illuminate
Yes
Trouble with the motor
re-lay, solenoid valve [due to1self test when driving above
6 km/h (4 mph)] or malfunc-
Notion of wheel speed sensor
tt
Is there one-sided braking, insufficientNo
braking force or malfunction of ABS c
CONTINUE TO
NEXT PAGE
operation?
Yes
4
Trouble condition
One-sided braking Insufficient braking force
Decline in ABS function
(Wheels easily lock when there is sud-
den braking.)
ABS sometimes functions even when
there is no sudden braking.
(ABS opera-
tion vibration is transmitted.) Major causes
l Mechanical lock of HU solenoid valve
l Hydraulic line in HU is clogged.
l Malfunction in HU solenoid valve op- eration
l Hydraulic line in HU is clogged.
l Insufficient wheel speed sensor out- put voltage (sensor malfunction, too
large a gap between sensor rotor or
missing rotor teeth or temporarily
broken wire in sensor harness) 8 Malfunction of ABS ECU Remedy
Check, using flow
chart D. (Refer to
P.35-45.)
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Remedy
Check HU operation (Refer to
P.35-36.) and, if necessary,
replace HU. If HU is normal, check
structural parts for normal
braking. (Refer to
P.35-12.)
Check wheel speed sensor
(Refer to P.35-126.) and, if
necessary, replace sensor,
adjust gap or replace rotor. If tests indicate that there are
no mechanical or electrical
failures, replace the ECU.