1991 MITSUBISHI ECLIPSE ignition

BRAKES - Anti-lock Braking System Troubleshooting5-13With the ignition key in the “ON”
posi-Nol
tion, do other warning lights illuminate?
II
YesCheck fuse No. 11. If it is
blown, correct the cause of
the blown fuse and then
replace the fuse.
Does voltage between
har-NoThe harness between thenessconnector terminalcombination meter from
No. 14 and ground indicate) fuse No.1 1 is broken.
battery voltage?
II
Yes
Repair harness.Circuit in combination meter
is broken.Repair or replace
com-
* bination meter.
Turn the ignition switch OFF an
(check.
IIs the ABS warning light normal? (Check
for burned bulb.)
No L A&zed%rning light bulb -Are instrument panel wiring harness,
_Noengine compartment wiring harness,~ Connect connectors firmly.
(Check for pins pulled out or
bent, repair as needed.) body wiring harness and ABS wiring
harness connectors connected properly?drive circuits. Check and repair both

BRAKES - Anti-lock Braking System Troubleshooting5-15
--
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.
MAINIGNITION
FUSIBLELINK
@IEYCH
z
A:7
J/B
rb
0
10A
I
:c
r
I
1vAI23
f
! 127ABS ECUCheck, using check chart
E-l -E-6.Check warning light drive
circuit.
t
Does the ABS warning lightNoShort in ECU transistor
remainilluminated even
with the ECU connector dis-
connected?
I
1 YesIReplace
I
Does the ABS warning light
remainilluminated even
with the ECU connector dis-
connected?
Yes
IReplace HU or replacevalve relay.I

5-16BRAKES - Anti-lock Braking System Troubleshooting
SUB
IGNITION
FUSIBLE
SWITCHLINK
@W.2)
I I18
ABS ECU9
SELF-DIAGNOSISCHECKCONNECTOR
No - Correct cause of blown
fuse and replace fuse.
YesWith the ignition key in the
“ON” position,
does ,thf
E;;;; relay make a click
’ Yes ’Disconnect ECU connector
and check harness
connec-
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?
---j-z-
III
I -11 Repair harness.I
YesMalfunction of ABS ECU
Replace ABS ECU.

BRAKES - Anti-lock Braking System Troubleshooting5-17
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
IGI power source which is
not turned off even in the “START” position.
Consequently, in the “START” position, power is offand 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.
MAINIGNITIONFUSIBLESWITCHLINK @(iG1)I
J/B58
15
ABS ECUWith the ignition key in the
“ON” position, does voltagebetween body connector
terminal
No.8 and groundindicate the battery voltage?
Yes

5-18BRAKES - Anti-lock Braking System Troubleshooting
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 thethe valve relay test, etc.
125
El
ABS ECU
14A0597connector and check with
I
In the ignition key “ON”
_ No ~ Harness wire between
position, does voltage
be-ABS warning light and
tween terminal No.25 andECU is broken.
ground indicate battery vol-
tage?
YesRepair harness.
tMalfunction of ABS ECU
Replace ABS ECU.

BRAKES - Anti-lock Braking System Troubleshooting5-23
E-5Abnormality of valve relay drive circuit
~- [Explanation]Ii ;.
\jVhen the ignition switch is turned ON, the ABSnormal. In addition, normally it monitors whether qrECU 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. Then, if the
the valve relay and valve power monitor line voltagesupply of power to the valve power monitor,line is
tocheck whether the valve relay operation isinterrupted, the warning light illuminates.
IGNITIONMiN&USIBLESWITCH(IGI)
ECU
1When the valve relay is
checked, are the following
conditions found?Valve relay malfunction
I
No. 85-No. 86:resistancevalue 60-120 QNo. 30-No. 87a: continuity
No. 30-No. 87: No continui-
tYWhen battery voltage is ap-
plied between terminals
No. 86 and No. 85 grounded.No.
30-No. 87: continuity
No. 30-No. 87a: no continui-
Install the valve relay and
remove the HU connec-
t the HU harnesandremove the ECU con-Is there continuity between
body connector terminal No.
22 and ground?
Yes
Valve relay drive circuit is
normal.

BRAKES - Anti-lock Braking System Troubleshooting5-25
TROUBLESHOOTING (ABS-AWD)Confirm condition in the following way and diagnosis accordingly.
C
F
>oes the ABS warning light illuminate as described
relow up to the time the engine starts?
1) When the ignition key is turned to the “ON”
position, the ABS warning light illuminates for
approximately 1 second due to the ABS ECU (asa self check of the valve relays is performed),
then it blinks four times and goes out and stays
out.power to the ABS ECU is interrupted and the
ABS warning light remains lit because the valve
relay is OFF.
t:2) With the ignition key in the “START” position,(3) When the ignition key is turned from the
“START” position to the “ON” position, the
ABS warning light illuminates for approximately
1 second (during this time a recheck of the valverelays is performed), then it blinks four times
and then goes out and stays out.IO1
-1 sec. 1 sec.1
sec.1 sec.
14AO594
YesCONTINUE TO NEXT PAGE
No
No.
1
2
3
Trouble condition
ABS warning light does not light up at all.
ABSwarninglightOFFIgnitionkey
ACC.
LO;-+
14AOSSOWhen the ignition key is turned to the
“ON” position, it remains lighted.
4BSNamingight
0:7gnition
wACC.
LO:+14A0591Does not illuminate when ignition key is
in “START” position.
4BSNamingightONOFF
14A0595
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 self
diagnosis
l Short in ECU warning light drive circuitl Malfunction of ECU
l Malfunction of valve relay
l Break in harness between ABS warn-
ing light and HU
l Break in harness between HU and
body groundRemedy
Check, using flow
chart A. (Refer to
P.5-27.)
Check, using flow
chart B. (Refer to P.5-30.)
Check, using flow
chart C. (Refer to
P.5-
32.)

5-26BRAKES - Anti-lock Braking System Troubleshooting
No.Trouble conditionMajor causesRemedyAfter the ignition key is turned to the
l Break in harness for ECU warningCheck, using flow“ON” position, it blinks once and thenlight drive circuitchart D. (Refer to P.5-illuminates when it is turned to the
l Malfunction of ECU33.)“START” position. When the key is
returned to the “ON” position, the light
4blinks again. (Blinking with the ignition
key in the “ON” position is synchronized
with operation noise of the valve relay.)
ABSwarning
light
0:~
Ignition
keyACC. iv-
14A0593CONTINUED FROM
PREVIOU? PAGE
I ,
Does the ABS warning light illuminateYes* Check, following trouble
when starting to drive the car?L Trouble with the motor re-lay, solenoid valve [due to
self test when driving above
6 km/h (4 mph)] or malfunc-source check charts E-l -E-7.
Notion of wheel speed sensor
Normal
YesTrouble condition
Major causes
RemedyOne-sided brakingl Mechanical lock of HU solenoid valveCheck HU operation and, if
Insufficient braking forcel Hydraulic line in HU is clogged.
necessary, replace HU.
If HU is normal, check
Decline in ABS functionl Malfunction in HU solenoid valve op- structural parts for normal
(Wheels easily lock when there is
sud-
erationbraking. (Refer to P.5-2.)den braking.)l Hydraulic line in HU is clogged.
ABS sometimes functions even whenl Insufficient wheel speed sensor
out-Check wheel speed sensor
there is no sudden braking. (ABS opera-put voltage (sensor malfunction, too (Refer to P.5-82.) and, if
tion vibration is transmitted.)
large a gap between sensor rotor, necessary, replace sensor,
missing rotor teeth or temporarily adjust gap or replace rotor.
broken wire in sensor harness)
If tests indicate that there are
l Malfunction of ABS ECU
no mechanical or electrical
failures, replace the ECU.