2000 MITSUBISHI MONTERO Service Repair Manual

ABS <4WD> -General Information35B-2
GENERAL INFORMATION
ABS has been adopted as standard equipment
in all vehicles to maintain directional stability and
steering performance during sudden braking.
The ABS control method used is a 4-sensor,
4-channel method (previous models: 4-sensor,
3- channel method
)which allows the brake
pressures for all four wheels to be controlled
independently of each other. The system has the
following features.
DEBD
*(Electronic Brake force Distribution
system) control has been added to provide the
ideal braking force for the rear wheels.DThe hydraulic unit function has been integrated
with the hydraulic brake booster (HBB).
DSelect solenoid valves (two valves for FL and
FR) have been adopted in order to reduce the
pedal kickback and improve the operation
feeling when the ABS is operating.
DIndependent 4-wheel control is carried out wile
the vehicle is turning in order to increase the
braking force.
NOTE
*EBD: Electronic Brake-force Distribution
EBD CONTROL
In ABS, electronic control method is used whereby
the rear wheel brake hydraulic pressure during
braking is regulated by rear wheel control solenoid
valves in accordance with the vehicle’s rate of
deceleration and the front and rear wheel slippage
which are calculated from the signals received from
the various wheel sensors. EBD control is a control
system which provides a high level of control for
both vehicle braking force and vehicle stability. The
system has the following features.
DBecause the system provides the optimum rear
wheel braking force regardless of the vehicle
laden condition and the condition of the road
surface, the system reduces the required pedal
depression force, particularly when the vehicle
is heavily laden or driving on road surfaces
with high frictional coefficients.DBecause the duty placed on the front brakes
has been reduced, the increases in pad
temperature can be controlled during front
brakes applying to improve the wear resistance
characteristics of the pad.
DControl valves such as the proportioning valve
are no longer required.
SPECIFICATIONS
ItemSpecifications
ABS control method4-sensor, 4-channel
No. of ABS rotor teethFront50
Rear50
ABS speed sensorTypeMagnet coil type
Gap between sensor and rotor mm0.9 (non-adjustable type)


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S
to p la m p sw it c h G
se nso r C
ente r dif f e re ntia llo ck sw it c h or
4 W D dete ctio n sw it c h H
yd ra ulic bra ke
b ooste r (H BB) V
alv e re la y D
ia gnosis co nnecto r A
BS-E C U W
heels p eed se nso r
w
ww.W ork sh opM an uals .c o .u k
P urc h ased f r o m w ww.W ork sh opM an uals .c o .u k

S
ER VIC E SPEC IF IC ATIO NS
I te m S
ta ndard va lu e C
ontr o lso le noid va lv e re sis ta nce W 4
.7 5 -5.2 5 O
UT 2
.0 -2.4 S
ele ct so le noid va lv e re sis ta nce W W
heelsp eed se nso r te rm in alre sis ta nce kW W
heelsp eed se nso r in su la tio n re sis ta nce kW N
o. N
am e A
pplic a tio n M
B991502 M
UT-II su b as-
s e m bly C
heckin g th e ABS
( D ia gnosis dis p la y usin g th e MUT-II ) M
B991529 D
ia gnosis co de
c h eckin g harn ess C
heckin g th e ABS
( D ia gnosis dis p la y usin g th e ABS warn in g
l a m p) M
B991348 T
e st harn ess se t C
heckin g th e G se nso r E
xp la natio n of sym pto m W
hen th e engin e sta rts , a kn ockin g so und ca n be heard co m in g fr o m
t h e engin e co m partm ent. T
his so und occu rs as a re su lt o fs yste m
o pera tio n ch eckin g, and is not a
m alf u nctio n. 1
. The bra ke pedalfe elin g ch anges and nois e is genera te d.( R attlin g)
2 . When th e ABS is opera tin g, nois e is genera te d by parts of th e
v e hic le ch assis as co ntr o ltu rn s on and off . (T hum p: su sp ensio n;
s q ueak: ty re s) T
his is th e so und of norm al syste m
o pera tio n, and is not a malf u nctio n. S
hocks are fe lt if th e bra ke pedal is depre sse d when driv in g at lo w
s p eed. T
his is due to syste m opera tio n
c h eckin g (s ta rtin g -o f ch eck when th e
v e hic le sp eed re ach es a ce rta in
n um ber of km /h ) and is not a
m alf u nctio n.

ABS <4WD> -Troubleshooting35B-7
INSPECTION CHART FOR DIAGNOSIS CODES
Diagnosis code
No.Diagnosis itemReference page
11Wheel speed sensor (FR) system (open circuit or short - circuit)35B-8
12Wheel speed sensor (FL) system (open circuit or short - circuit)35B-8
13Wheel speed sensor (RR) system (open circuit or short - circuit)35B-8
14Wheel speed sensor (RL) system (open circuit or short - circuit)35B-8
15Wheel speed sensor system (output signal abnormality)35B-9
16ABS-ECU or valve relay power supply system (abnormal voltage
drop or rise)35B-10
21Wheel speed sensor (FR) system35B-8
22Wheel speed sensor (FL) system35B-8
23Wheel speed sensor (RR) system35B-8
24Wheel speed sensor (RL) system35B-8
26Center differential lock switch system35B-11, 12
27Rear differential lock switch system35B-11, 12
32G sensor system35B-13
33Stop lamp switch system35B-14
41Control solenoid valve (FR)
systemIf there is no response to the
solenoid valve drive signal35B-15
42Control solenoid valve (FL)
systemcorresponding to each respec-
tive item
43Control solenoid valve (RR)
system
44Control solenoid valve (RL)
system
45Changeover solenoid valve
(FR) system
46Changeover solenoid valve
(FL) system
51Valve relay system (ON problem)35B-16
52Valve relay system(OFFproblem)35B-17
55HBB systemCarry out HBB troubleshoot-
ing. (Refer to GROUP 35A.)
63ABS-ECU system35B-32 (ABS-ECU replace-
ment)
NOTE
*: Code No.16 is erased from the memory if the condition returns to normal.


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ABS <4WD> -TroubleshootingABS <4WD> -Troubleshooting35B-8
INSPECTION PROCEDURE CLASSIFIED BY DIAGNOSIS CODE
Code No. 11, 12, 13, 14 Wheel speed sensor system
(open circuit or short-circuit)Probable cause
Code No. 21, 22, 23, 24 Wheel speed sensor system
Code Nos. 11, 12, 13, 14 are output when theopencircuit or short-circuit
detection carried out by the ABS-ECU hardware circuit detects that there is an
opencircuit or short-circuit in the (+) or ( - ) wire in one of the four wheel speed
sensors and signals are consequently notbeing input.DMalfunction of wheel speed sensor
DMalfunction of harness or connector
DMalfunction of the ABS-ECU
Code No. 21, 22, 23, 24 are output at the following times:
DIf an opencircuit cannot be verified, but one or more of the wheel speed
sensors does not output any signal when the vehicle speed is a certain
number of km/h or higher.
DWhen a problem such as chipped orplugged - uprotor tooth is detected, or if
the sensor output drops and anti - skid control is continuously carried out due
to a malfunctioning sensor or a warped ABS rotor.DMalfunction of wheel speed sensor
DMalfunction of harness or connector
DMalfunction of ABS rotor
DExcessive clearancebetween sensor and ABS
rotor
DMalfunction of the ABS-ECU
DMalfunction of wheel bearing
NG
NG
Replace the ABS-ECU.
NG
Repair
OK
Check the trouble symptoms.
OK
Check the following connector:E-106
OK
Wheel bearing check
(Refer to GROUP 26, 27 -
On-vehicle Service.)
NG
Replace
OK
ABS rotor check
(Refer to P.35B-33.)
NG
Replace
Wheel speed sensor check
(Refer to P.35B-34.)
OK
Wheel speed sensor output voltage check (Refer to P.35B-27.)
OK
Check the following connectors:A-04 , A-23, A-39,
D-124, D-143 , E-10, E-106, F-17, G-11, G-15
Wheel speed sensor installation checkNG
Repair
OK
Measure at ABS-ECU connector E-106.
DDisconnect the connector and measure at the harness
side.
DFront: resistance between 10 – 23, 7 – 20
Rear: resistance between 8 – 21, 9 – 22
OK:1.0 - 1.5 k
WNG
NG
Replace
NG
Repair
OK
Check the trouble
symptoms.
NG
Check the harness wire, and repair if necessary.
DBetween each wheel speed sensor and ABS-ECU
Wheel speed sensor check (Refer to P.35B-34.)


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ABS <4WD> -Troubleshooting35B-9
Code No. 15 Wheel speed sensor system (output signal
abnormality)Probable cause
This malfunction code is output when any one of the wheel speed sensor output
signals during driving is abnormal (exceptopen andshort circuit).DUneven tyre size for all four wheels
DIncorrect wheel speed sensor installation
DMalfunction of wheel speed sensor
DMalfunction of harness or connector
DMalfunction of ABS rotor
DMalfunction of wheel bearing
DMalfunction of the ABS-ECU
NG
Check the harness wire, and repair if necessary.
DBetween each wheel speed sensor and ABS-ECU
OK
Wheel bearing check
(Refer to GROUP 26, 27 - On-vehicles Service.
NG
Replace
OKNG
Replace
NG
Replace the ABS - ECU.
OK
Check the trouble
symptoms.
NG
Repair
OK
Check the following connector:E-106
OK
Wheel speed sensor output voltage check (Refer to P.35B-27.)NGWheel speed sensor check (Refer to P.35B-34.)
NG
Wheel speed sensor installation checkNG
Repair
Are the tyres on all four wheels of identical size?NOFit tyres which are of identical size.
YES
Check the trouble symptoms.
Check the ABS rotor (Refer to P.35B-33).


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