1989 MITSUBISHI GALANT Main fusible

35-42
SERVICE BRAKES - Anti-lock Braking System Troubleshooting
BABS warning light illuminated after the engine is started and remains on\
.
[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 possibility
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.
MAINFUSIBLELINK @
IGNITION
SWITCH
(IG1)
ILOIE;NATION
+10
3
@izJ”,HUZ8 p:r12 /e-,
xx
I
I
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; 16 4=
9
II
d
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I -LQ-7 ABS ECUm1
: Non-Turbo . Turbo: Non-Turbo Is there on-board diagnosticNocCONTINUE TO
output? (Is there communi- NEXT PAGE
cation with scan tool?)
I
Yes
Does diagnostic troublecode output display normalcodes?
No . Check, using the diagnos-tic trouble code checkchart. (Refer to P.35-38.)IIILI
Short in harness betweenrgl;r ECU and ABS warning) Repair harness or replacecombination meter.
II
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SERVICE BRAKES - Anti-lock Braking System Troubleshooting35-43
MAINFUSIBLELINK @
IGNITION
KgCHm

l
CONTINUED FROM
PREVIOUS PAGE
CONNECTOR
t ,
Is there continuity betweenNo FHarness wire between
body harness connector
ter-data link connector and minals

No.23 and No.24, andABS ECU is broken.
data link connectors No.4 &No.1 O?I
Repair harness.
Yes
I
1 Malfunction of ABS ECUI1-4 Replace ABS ECU.III1
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1 Yes
No - Correct cause of blown fuse and replace fuse.
r
L
W
ith the ignition key
in theNo ~ Is power relay normal?
“ON” position, does the (Refer to P.35-74.)power relay make a “click”noise?
YesNoYes
tI ,
Disconnect ECU connector
and check harness connec-
tor.t
Replace power relay.1
W
ith the ignition key in the
NoHarness wire between
“ON” position, does voltage- power relay and ECU is
between ECU connector ter-
broken.
minal No. 18 and ground in-
dicate the battery voltage?
4
Repair harness.
Yes
tp
Is there continuity betweenNoECU ground line broken
body harness terminal
s
No.9
and No. 34, and
c
ground?Repair harness.I
Yes

35-48SERVICE BRAKES - Anti-lock Braking System Troubleshooting
I IE-3When diagnostic trouble code “21 G SENSOR” is displayedI
[Explanation]
The ABS ECU outputs this diagnostic trouble code
in the following cases.
lOFF trouble turning G sensor OFF (It is judged
that the
G sensor continues to be OFF for more
than approximately 13 seconds except when the
vehicle 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.
ABSPOWERRELAY
MAIN FUSIBLEIGNITIONLINK @SWITCH (IG2)
G-SENSOR
q
ABS ECU
II21314 15161 ~/819110111l12l1P/14l15~~6l17l16~~19120121122123l24125l26l27128129/30131j32b3134(15~14AO702
Is G sensor normal?(Refer to P.35-132.)
NoReplace G sensor.
1 Yes
Remove the ABS ECUconnector and check atthe harness connector.
I
With the ignition key “ON”No m The harness between thedoes the voltage betweenG sensor and the ABS
terminal No.6
and ground
ECU is broken.
indicate battery voltage?
Yes
*
Repair harness.
Replace ABS ECU.
1 TSB Revision

SERVICE BRAKES - Anti-lock Braking System Troubleshooting35-49
1 E-4 1 When diagnostic trouble code “22 STOP SW” is displayed
[Explanation]
The ABS ECU outputs this diagnostic trouble code
in the following cases.
lStop light switch may remain on for more than
15 minutes without the ABS functions.
lThe harness wire for the stop light switch maybe open.
[Hint]
If the stop light operates normal, the ABS harness
wire for the stop light switch input circuit to the ECU
is broken or there is a malfunction in the ABS ECU.
SUB FUSIBLELINK 0
WITH
AUTO-CRUISE CONTROL
SWITCH -G
_.ABSECU
F-l
14A0663
Do the stop lights light up - Noand go out normally?~ Check the stop light re-lated circuit and repairproblem spots.
Yes
connect the ABS EC
connector and inspect at
the harness side connec-
When the brake pedal isNoHarness wire betweenpressed forcefully, does thevoltage between connectorstop light switch and ABSECU is broken.terminal No. 29 and groundindicate battery voltage?
Yes
1
Repair harness.
1
Malfunction of ABS ECU Replace ABS ECU.I

SERVICE BRAKES - Anti-lock Braking System Troubleshooting35-51
E-5When diagnostic trouble code “51 VALVE RLY” is displayed
[Explanation]
When the ignition switch is turned ON, the ABS
ECU switches the valve relay OFF and ON for an
initial check, compares the voltage of the signal to
the valve relay and valve power monitor line voltage
to check whether the valverelay operationis
normal. In addition, normally it monitors whether or
not there is power in the valve power monitor line
since the valve relay is normally ON. Then, if the
supply of power to the valve power monitor line is
interrupted, this diagnostic trouble code will output.
MAIN FUSIBLE$tW&N
LINK @I(IGl)
gEli!z$; lf*x**
IT
510
IU-412 &-,8
ABS ECU
: Non-Turbo . Turbo: Non-Turbo y+iw+w;,aay;check thy
When the valve relay i
s
checked, are the following
conditions found?No. 85-No. 86:resistance
value 60-120 52No.30-No.87a: continuity
No. 30-No. 87: No continui-
When battery voltage is ap- plied between terminals
No. 86 and No. 85 grounded.
No.30-No.87: continuity
No. 30-No. 87a: no continui-
t
y
remove the HU connec-
\/
I With
the
ignition key “ON”
,
No c HU power harness wire is
does the voltage betweenbroken?the connector terminal No.
12 and ground indicate bat- tery voltage? I
IRepair harness.
YesIIIbI\I
Does resistance between
body connector termina
l
No. 2 and terminal No. 27 in-
dicate
60-120 ohm?
IYes
Is there continuity between
body connector terminal No.
22 and ground? Repair harness.
ABS ECU malfunction Replace ABS ECU.
1 TSB Revision1

35-52SERVICE BRAKES - Anti-lock Braking System Troubleshooting
E-7When diagnostic trouble code “52 MOTOR RLY” is displayedI
[Explanation][Hint]
The ABS ECU outputs this diagnostic trouble code forIf there is motor operation noise when wheel speed
the motor relay and motor in the following cases. exceeds Gkm/h
(4mph) when starting up after the
l When the motor relay does not function engine is started, or when there is forced scan tool
l When there is trouble with the motor
itself and itdrive, there is a broken or short circuited motor
does not revolve monitor wire.
l When there is trouble with the motor itself and it
the motor does not revolve
l When the motor continues to revolve Yes
Broken wire or short cir-
-Inoise when wheel
speedcuit in motor monitor line
MAIN FUSIBLE
LINK @&
1 j 2 I3 I4 I5 I6 I 7 18 I9 l10l11112113114115116l17 1819p0~1122~3~24l2S~26I27(2~29130131l32l33l3~~3~
(Remove the motor relay>
r
l
-
\
/4~
Remove the motor relay and -check resistance values.No c Motor relay malfunction
No. 85-No. 86:resistance4
value 30-60
QNo.30-No.87: no continui-
Replace motor relay.
t
y
Battery voltage is applied on
terminals No.86
and
No.85groundedNo.30-No.87: continuity 1Yes
Is pump motor ground con-
No
netted normally?
Connect ground wire.
lYes
<
Install motor relay and
move HU connector.
Does voltage between body
connector terminal 11 and
No ) Broken wire in pum
p
ground indicate battery vol- motor power circuit
tage?
4
Yes Repair the harness.I
tor and
remove theECU
Is resistance between body - No - Malfunction of harness
connector terminal No. 2 andNo No.26
30-60 ohms? between HU and ECUI
4 Yes.
Repair harness.II
ABS ECU malfunction
Replace ABS ECU.I
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SERVICE BRAKES -Service Adjustment Procedures35-75
14AO197
FLAT BATTERY REMEDYM35FOAF
When booster cables are used to start the engine when the
battery is completely flat and then the vehicle is immediately
driven without waiting for the battery to recharge itself to
some extent, the engine may misfire, and driving might not be
possible. This happens because A.B.S. consumes a great
amount of current for its self-check function; the remedy is to
either allow the battery to recharge sufficiently, or to remove
the fuse for A.B.S. circuit, thus disabling A.B.S.
The A.B.S. warning light will illuminate when the main fusible
link (for A.B.S.) is removed.
After the battery has sufficiently charged, install the main
fusible link (for A.B.S.) and restart the engine; then check to be
sure the A.B.S. warning light is not illuminated.
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BRAKE FLUID PRESSURE SWITCH CHECK
hl35FOAL
(1) Disconnect the hydraulic pressure switch connector.
(2) Check the continuity between the terminals of hydraulic pressure switch.
Condition Between terminals
Brake pedal not depressed
No conductance
Brake pedal depressed lightlyNo conductance
Brake pedal depressed
stronglyConductance