1991 MITSUBISHI ECLIPSE ignition

BRAKES - Anti-lock Braking System Troubleshooting5-27
AABS warning light does not light at all.I-. [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.
MAIN FUSIBLE
LINK
@
2
c-4
I 1~0~0~fWW-i
m2 ac
HU&,52&8--1
III
IA x A ,c
VALVE "I
RELAYI
1 IRELAY /--+I1 &-I I
\, J,. \ ,I L-1
I-----------A
I I
[Hint]If other warning lights do not light up either, fuse is
probably blown.
IGNITIONIGNITIONSWITCH (IG2)SWITCH (IGI)
10A10A p,
*2\I6-IM"
7,,14112131415161718I 9 I
iE4~oWERI.0(1111211311915116117
#$II;NATION
58
ABS ECU125
GNDGNDT7”

5-28BRAKES -Anti-lock Braking System Troubleshooting
With the ignition key in the “ON”
posi-NoCheck fuse No.ll. If it is
tion, do other warning lights illuminate?blown, correct the cause of
the blown fuse and then
replace the fuse.
YesTurn the ignition switch OFF and
Does voltage between
har-NOThe harness between the
nessNo. 14 and ground indicate
battery voltage?) fuse No.1 1 is broken.
YesCircuit in combination meter
is broken.
tRepair or replace com-
bination meter.II
IIIs the ABS warning light normal? (CheckNO) ABS warning light bulbReplace ABS warning
for burned bulb.)
burned.* light bulb.
I
Yes
- No
Are instrument panel wiring harness,
engine compartment wiring harness,
body wiring harness and ABS wiring
harness connectors connected properly?
c Connect connectors firmly.
(Check for pins pulled out or
bent, repair as needed.)
YesBroken wire in ECU, valve relay or both
drive circuits. Check and repair both
circuits.

5-30BRAKES - 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 thesystem or when the warning light drive circuit is
short circuited.
MAINIGNITIONFUSIBLELINK
@SWITCH(IGl)
ABS ECU
JCheck, using check chart
E-l -E-7.with the ECU connector
dis-
YesDoes the ABS warning light
NoShort in HU harness or
remainilluminated even
with the ECU connector dis-m sticking of valve relay
contact
connected?I
YesReplace HU or replace
valve relay.
ItShort in harness between
IT$Uhx ECU and ABS warningc Repair harness or replace
combination meter.

BRAKES - Anti-lock Braking System Troubleshooting5-31
SUBIGNITION
%TB(kEzYCH
IODE
;LLF-FIAGNOSIS
CONNECTOR
I Yes1,
With the ignition key in the
No _ Is power relay normal?
“ON” position, does the
(Refer to P.5-52.)power relay make a “click”:
noise?LDisconnect ECU connector
and check harness connec-Replace power relay.
tor.
YesWith the ignition key in the
“ON” position, does voltage
between ECU connector ter-
minal No. 18 and ground in-
dicate the battery voltage?
Yes
Yes
Replace ABS ECU.

5-32BRAKES -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 isand the ECU turns the valve relay OFF. If the
turned off in the “START” position. The ABSwarning light does not illuminate at this time, there
warning light uses the
IGI power source which isis trouble in the warning light circuit on the valve
not turned off even in the “START” position.relay side.
Consequently, in the “START” position, power is off
MAINIGNITIONFUSIBLESWITCHLINK @I(IGl)J/B
“62
I .1411213141516l7l61911112113114115U6i,79
@COMBINATIONAL METER
“58ABS ECU
1410000
hydraulicunit (HU) connector and
>\/I
1With the ignition key in the
“ON” position, does voltage
between body connector
terminal No.8 and ground
indicate the battery voltage?
Is there continuity between
No~Broken line between HU
body connector terminaland body groundNo.9 and ground?
I
YesIs there continuity between
HU connector terminal No. 8and terminal
No.9?
YesRemove the valve relay. Is
there continuity between
terminal No. 87a and No. 30?
I
Yes1 Replace valve relay.
HU harness malfunction
I
1 Replace HU.

BRAKES - Anti-lock Braking System Troubleshooting5-33
DABS warning light blinks once after the ignition key is turned to the “ON” position. It
illuminates in the “START” position and blinks once again when turned to the “ON” position.*-_
[Explanation ]When power flows, the ABS ECU turns on the
harness between the ECU and the warning light, thewarning light for approximately 1 sec. while itlight 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.
Y
x %l4
9
4
n. 58
ABS ECU
14A0597
EC
4connector and check with
he harness connector. /\/
IIn the ignition key “ON”
position, does voltage be-
tween terminal
No.25 andground indicate battery vol-
tage?
Replace ABS ECU.I

5-36BRAKES - Anti-lock Braking System Troubleshooting
E-3Abnormality of G sensor circuit
[Explanation]The ABS ECU turns on the warning light 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
lWhen there is a broken wire or short circuit in
the harness for the
G sensor system.
PlUN; F;SIBLEIGNITIONSWITCH (IG2)J/B
G-SENSOR
E-lABSECU
14AO609
Is G sensor normal? (ReferNoto
P.5-86.)Replace G sensor.
I YesWith the ignition key “ON”
_ No m The harness between the
does the voltage betweenG sensor and the ABS
terminal No.6 and groundECU is broken.
indicate battery voltage?
IG sensor circuit is normal.I

5-38BRAKES - Anti-lock Braking System Troubleshooting
E-5Abnormality of solenoid valve drive circuit
[Explanation]*>The ABS ECU normally monitors the solenoid valve
when turned OFF, the ECU determines the solenoid%’ -’drive circuit.coil wire is broken/short circuited or the harness is
If no current flows in the solenoid even if the ECUbroken/short circuited and then the warning light
turns the solenoid ON or if it continues to flow evenlights up.
IGNITIONSWITCH(IGI)
7JIB------_-_tor and check with the
side connector.
Connect HU
1OP connec-
disconnect ECU con-
>Is the solenoid valve resis-
tance value within the range
of the standard values when
measured at the ECU con-
nector?Standard value:
3.0-3.2 Q
Yes1
II
I
Solenoid valve drive circuit isnormal.I
NoReplace HU.I
NoIs the resistance value for
the solenoid valve within the
range ofthe standard
values?Standard value:
3.0-3.2 Q, IYes ,
1
JThe harness wire for the
solenoidvalvecircuit
whose resistance value is
outside the range of the
standard value is broken
or short circuited.,-‘he-
-Repair