1997 MITSUBISHI TRITON Workshop Manual

ABS <2WD> ± Troubleshooting35B-14
INSPECTION CHART FOR TROUBLE SYMPTOMS35201140142
Get an understanding of the trouble symptoms and check according to the inspection procedure chart.
Trouble symptomsInspection
procedure No.Reference
page
Communication with MUT-II
is notpossible
Communication with all systems is not possible.135B-15
is not ossible.
Communication with ABS only is not possible.235B-15
When the ignition key is turned to ªONº (engine stopped), the ABS warning lamp does
not illuminate.335B-16
After the engine starts, the ABS warning lamp remains illuminated.435B-16
When the ignition key is turned to ªSTARTº, the ABS warning lamp does not illuminate.535B-17
After the ignition key is turned to ªONº, the ABS warning lamp blinks twice, and when
turned to ªSTARTº, it illuminates. When returned to ªONº, the lamp flashes once, and
then switches off.635B-17
Faulty ABS operationUnequal braking power on both sides735B-18
Insufficient braking power
ABS operates under normal braking conditions
ABS operates before vehicle stops under normal
braking conditions
Large brake pedal vibration (Caution 2.)±±
Caution
1. If steering movements are made when driving at high speed, or when driving on road surfaces
with low frictional resistance, or when passing over bumps, the ABS may operate even though
sudden braking is not being applied. Because of this, when getting information from the customer,
check if the problem occurred while driving under such conditions as these.
2. During ABS operation, the brake pedal may vibrate or may not be able to be depressed. Such
phenomena are due to intermittent changes in hydraulic pressure inside the brake line to prevent
the wheels from locking and is not an abnormality.

ABS <2WD> ± Troubleshooting35B-15
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMS
Inspection Procedure 1
Communication with MUT-II is not possible.
(Communication with all systems is not possible.)
Probable cause
The reason is probably a defect in the power supply system (including earth) for
the diagnosis line.
Malfunction of connector

Malfunction of harness
Refer to GROUP 13A ± Troubleshooting.
Inspection Procedure 2
Communication with MUT-II is not possible.
(Communication with ABS only is not possible.)
Probable cause
When communication with the MUT-II is not possible, the cause is probably an open
circuit in the ABS-ECU power circuit or an open circuit in the diagnosis output circuit.
Blown fuse

Malfunction of wiring harness or connecter

Malfunction of ABS-ECU
OK
Check trouble symptoms.NGReplace the ABS-ECU.
OK
Check the following connectors.
C-62 and C-64NG
Repair
OK
Check trouble symptoms.NGCheck the harness wire between the
ignition switch and the ABS-ECU, and
repair if necessary.
OK
Measure at ABS-ECU connectors C-62
and C-64

Disconnect the connector and
measure at the harness side.

Continuity between 4, 15, 16, 25
(C-62), 42 (C-64) ± body earth
OK:ContinuityNG
OK
Measure at ABS-ECU connector C-62

Disconnect the connector and
measure at the harness side.

Ignition switch: ON

Voltage between 13 ± body earth
OK:System voltageNGCheck the following connectors.
C-88, C-86 and C-02NG
Repair
OK
Check trouble symptoms.NGCheck the harness between the ABS-
ECU and diagnosis connector, and re-
pair if necessary.
Measure at diagnosis connector C-35
and ABS-ECU connector C-64

Disconnect the connector and
measure at the harness side.

Continuity between the following
terminals
OK:Continuity
ABS-ECU side
Diagnosis connector sideNGCheck the following connector.
C-02NG
Repair
Repair 47
1367

ABS <2WD> ± Troubleshooting35B-16
Inspection Procedure 3
When ignition key is turned to ºONº (engine stopped),
ABS warning lamp does not illuminate.
Probable cause
When current flows in the ABS-ECU, the valve relay turns from off to on, off and
back to on again as the initial check. So the ABS warning lamp will illuminate twice
when the valve relay is off even if there is a problem with the circuit between the
ABS warning lamp and the ABS-ECU.
Therefore, if the lamp does not illuminate, the cause may be: an open circuit in the
lamp power supply circuit, a blown lamp bulb, an open circuit in both the circuit between
the ABS warning lamp and the ABS-ECU and in the circuit between the ABS warning
lamp and the valve relay.
Blown fuse

Burnt out ABS warning lamp bulb

Malfunction of wiring harness or connector
OK
Check trouble symptoms.NGReplace the combination meter. NG
Repair
OK
Check the following connectors.
C-88, C-79, C-06, C-05 and C-02
OK
Check the harnesses between the valve
relay and connector C-02 and between
the ABS-ECU and connector C-02. Re-
pair if necessary.
OK
Measure at connector C-02:

Disconnect the connector and
measure at the male pin.

Ignition switch: ON

Does the ABS warning lamp
illuminate when terminal (3) is
earthed?
OK:IlluminatesNGCheck whether the ABS warning lamp
bulb is burnt out.NGReplace the ABS warning lamp bulb.
Fuse inspection, Multi-purpose fuse No.
11NGRefer to GROUP 00 ± Inspection Ser-
vice Points for a Blown Fuse.
Inspection Procedure 4
Even after the engine is started, the ABS warning lamp
remains illuminated.
Probable cause
The cause is probably a short-circuit in the ABS warning lamp illumination circuit.
Malfunction of combination meter

Malfunction of ABS-ECU

Malfunction of wiring harness
NOTE
This trouble symptom is limited to cases where communication with the MUT-II is possible (ABS-ECU
power supply is normal) and the diagnosis code is a normal diagnosis code.
No
Check the harnesses between the combination meter and the ABS-
ECU and between the combination meter and the valve relay. Repair,
if necessary.
No

Disconnect ABS-ECU connector C-64.

Disconnect valve relay connector A-39.

Ignition switch: ON

Does the ABS warning lamp switch off?Ye sReplace the ABS-ECU.
Disconnect connector C-02 and turn the ignition switch to ON.

Does the ABS warning lamp remain illuminated?Ye sReplace the combination meter.

ABS <2WD> ± Troubleshooting35B-17
Inspection Procedure 5
When ignition key is turned to ºSTARTº, ABS warning
lamp does not illuminate.
Probable cause
Current does not flow in the ABS-ECU when the ignition switch is turned to START.
Current flows in the ABS warning lamp even when the ignition switch is turned to
START. Therefore, the valve relay, which current is supplied through the ABS-ECU,
turns off when the ignition switch is at START. However, the warning lamp circuit
of the valve relay must turn on in turn. So the cause must be a defective circuit
on valve relay side.
Malfunction of wiring harness or connector

Malfunction of ABS-ECU
ABS valve relay check (Refer to
P.35B-28.)NGReplace the ABS valve relay.
OK

Disconnect valve relay connector
A-39.

Disconnect ABS-ECU connector
C-64.

Ignition switch: ON

Voltage between valve relay
harness-side connector terminal (3)
and body earth
OK:System voltageNGCheck the following connector and
diode.
C-02 and C-05NG
Repair
OK
Check trouble symptoms.NGCheck the harness between the com-
bination meter and valve relay, and re-
pair if necessary.
OK
Check the following connector.
A-39NG
Repair
OK
Check trouble symptoms.NGCheck the harness between the valve
relay and earth, and repair if necessary.
Inspection Procedure 6
The ABS warning lamp flashes twice after the ignition key
is turned to ºONº. The lamp illuminates when the ignition
key is turned to ºSTARTº, and when the key is returned to
ºONº, it flashes once.
Probable cause
The ABS-ECU causes the ABS warning lamp to illuminate during the initial check
(approx. 3 seconds). During the initial check, the valve relay turns from off to on,
off and back to on again. If there is an open circuit in the harness between the ABS-ECU
and the ABS warning lamp, the lamp will illuminate only when the valve relay is OFF
during valve relay test, etc.
Malfunction of wiring harness or connector

Malfunction of ABS-ECU

Disconnect valve relay connector
A-39.

Disconnect ABS-ECU connector
C-64.

Ignition switch: ON

Voltage between ABS-ECU har-
ness-side connector terminal (50)
and body earth
OK:System voltageNGCheck the following connector.
C-02NG
Repair
OK
Check trouble symptom.NGCheck the harness between the com-
bination meter and the ABS-ECU, and
repair if necessary.
OK
Check the following connector.
C-64NG
Repair
OK
Check trouble symptom.NGReplace the ABS-ECU.

ABS <2WD> ± Troubleshooting35B-18
Inspection Procedure 7
Brake operation is abnormal.
Probable cause
This varies depending on the driving conditions and the road surface conditions, so
problem diagnosis is difficult. However, if a normal diagnosis code is displayed, carry
out the following inspection.
Improper installation of wheel speed sensor

Incorrect sensor harness contact

Foreign material adhering to wheel speed sensor

Malfunction of wheel speed sensor

Malfunction of rotor

Malfunction of wheel bearing

Malfunction of hydraulic unit

Malfunction of ABS-ECU
OK
Check trouble symptom.NGReplace the ABS-ECU.
OK
Check the following connector.
C-62NG
Repair
NG
Measure at ABS-ECU connector C-62.

Disconnect the connector and
measure at the harness side.

Resistance value between terminals
10-23, 7-20, 8-21 and 9-22
OK:1.2 ± 1.4 kW
(The sensor harness and connector
should be moved while these
inspections are carried out.)NG
Repair
OK
Check trouble symptom.
OK
Check the following connectors.
A-01, A-07, F-01, F-16, D-01, and C-02NG
Repair
OK
Wheel bearing check. (Refer to GROUP
26 and 27 ± On-vehicle Service.)NG
Repair
OK
Rotor check. (Refer to P.35B-40.)NGReplace the rotor.
OK
Hydraulic unit check. (Refer to P.
35B-26.)
OK
Wheel speed sensor output voltage
check. (Refer to P. 35B-24.)NGWheel speed sensor check. (Refer to
P. 35B-39.)NGReplace the wheel speed sensor.
Wheel speed sensor installation check.NG
Repair

C
heck it e m C
heckin g r e quir e m ents N
orm al v a lu e 1
1 F
ro nt- rig ht w heel s p eed s e nso r P
erfo rm a te st r u n V
ehic le s p eeds d
is l
a ye d on th e 1
2 F
ro nt- le ft w heel s p eed s e nso r d
is la ye d o
n t
h e a
nd MUT II are 1
3 R
ear-rig ht w heel s p eed s e nso r a
n d M
UT 1
4 R
ear-le ft w heel s p eed s e nso r 1
6 A
BS-E C U p ow er s u pply v o lt a ge I
g nit io n s w it c h p ow er s u pply v o lt a ge a nd
v a lv e m onit o r v o lt a ge 9
± 16 V 3
3 S
to p la m p s w it c h D
epre ss th e b ra ke p edal. O
N R
ele ase th e b ra ke p edal. O
FF I
te m 0
1 S
ole noid v a lv e fo r fr o nt- le ft
w heel S
ole noid v a lv e s a nd p um p
m oto rs in th e h yd ra ulic u nit (
i li ti d) 0
2 S
ole noid v a lv e fo r fr o nt- rig ht
w heel (
s im ple in sp ectio n m ode) 0
3 S
ole noid v a lv e fo r r e ar w heel 3
s
A
ctiv atio n p atte rn
S ole
n oid
v a lv e
P um p
m oto r O
N
O FF E
nd 1
s H
yd ra ulic
p re ssu re
h old s H
yd ra ulic
p re ssu re
d ecre ase s

S
ig nal C
heckin g r e quir e m ents N
orm al c o ndit io n 1 O
utp ut to fr o nt- le ft h yd ra ulic
u nit s o le noid v a lv e ( O UT s id e) I
g nit io n s w it c h : O N ( W hen s o le noid v a lv e is
o ff a ppro xim ate ly 1 s e co nd a fte r e ngin e is s ta rte d) S
yste m v o lt a ge 2 O
utp ut to r e ar h yd ra ulic
u nit s o le noid v a lv e ( O UT s id e) 3 O
utp ut to r e ar h yd ra ulic
u nit s o le noid v a lv e ( IN s id e) 1
3 A
BS-E C U p ow er s u pply I
g nit io n s w it c h : O N S
yste m v o lt a ge I
g nit io n s w it c h : S TA R T 0
V 1
4 O
utp ut to fr o nt- le ft h yd ra ulic
u nit s o le noid v a lv e ( IN s id e) I
g nit io n s w it c h : O N ( W hen s o le noid v a lv e is
o ff a ppro xim ate ly 1 s e co nd a fte r e ngin e is s ta rte d) S
yste m v o lt a ge 2
6 O
utp ut to r e la y p ow er s u pply I
g nit io n s w it c h : O N S
yste m v o lt a ge 3
2 M
em ory p ow er s u pply A
lw ays S
yste m v o lt a ge 3
4 I
n put fr o m s to p la m p s w it c h I
g nit io n s w it c h : O N S
to p la m p s w it c h : O N S
yste m v o lt a ge S
to p la m p s w it c h : O FF 1
V o r le ss 3
6 M
UT-II S
eria l
c o m munic a tio n
w it h M UT-II . D
o n ot c o nnect th e M UT-II . 1
V o r le ss 3
7 O
utp ut to v a lv e r e la y I
g nit io n
s w it c h : O
N A
ppro xim ate ly 1 s e co nd a fte r e ngin e
i s s ta rte d, th e r e la y is o n. 2
V o r le ss O
N T
he s yste m r u ns d ow n. T he r e la y is
o ff . S
yste m v o lt a ge 3
8 O
utp ut to m oto r r e la y I
g nit io n s w it c h : O N A r
o xim ate ly 1 se co nd M
oto r is o n. 2
V o r le ss A
ro xim ate ly 1 s
e co nd M
oto r is o ff . S
yste m v o lt a ge 3
9 I
d le -u p s o le noid v a lv e ( + ) I
g nit io n s w it c h : O N ( T he m oto r is o n a ppro xim ate ly
1 s e co nd a fte r e ngin e is s ta rte d.) S
yste m v o lt a ge 4
1 O
utp ut to fr o nt- rig ht h yd ra ulic
u nit s o le noid v a lv e ( O UT s id e) I
g nit io n s w it c h : O N ( W hen s o le noid v a lv e is o ff
a ppro xim ate ly 1 s e co nd a fte r e ngin e is s ta rte d.) S
yste m v o lt a ge

ABS <2WD> ± Troubleshooting35B-21
Connector
terminal No.SignalChecking requirementsNormal condition
43Idle-up solenoid valve (±)Ignition switch: ON (The motor is on approximately
1 second after engine is started.)2 V or less
46Ignition switchIgnition switch: ONSystem voltage
Ignition switch: START0 V
47Input from diagnosis indication
selection
Connect the MUT-II.0 V
selection
Do not connect the MUT-II.Approx. 12 V
48Input from valve relay monitorIgnition switch: ONSystem voltage
49Motor monitorIgnition switch: ON
Approximately 1 second after
Motor is on.System voltage
A roximately 1 second after
engine is startedMotor is off.0.5 V or less
50Output to ABS warning lampIgnition
switch: ON
The lamp is switched off.System voltage
switch: ON
The lamp is illuminated.0 ± 2 V
52Output to front-right hydraulic
unit solenoid valve (IN side)Ignition switch: ON (When solenoid valve is off
approximately 1 second after engine is started.)System voltage