
GENERAL INFORMATION
ANTI-SKID BRAKE SYSTEM (ABS)35B-2
GENERAL INFORMATION
M2351000100409
FEATURES
The ABS ensures directional stability and controlla-
bility during hard braking.
For vehicles with this type of ABS, 4 sensors (4 
channels) are installed on front and rear wheels 
allowing independent left and right control.
The system has the following features:
•EBD (Electronic Brake-force Distribution system) 
control has been added to provide the ideal brak
-
ing force for the rear wheels.
•Magnetic encoder for wheel speed detection has 
been installed as a sensing device instead of the 
rotor.
•For wiring harness saving and secure data com-
munication, CAN* bus has been adopted as a 
tool of communication with another ECU.
NOTE: *: For more information about CAN (Control-
ler Area Network), refer to Group 54C, General Infor-
mation P.54C-2.
EBD CONTROL
In ABS, electronic control is used so 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 speed 
sensors. EBD control provides a high level of control 
for both vehicle braking force and vehicle stability. 
The system has the following features:
•Because the system provides the optimum rear 
wheel braking force regardless of vehicle load 
condition and the condition of the road surface, 
the system reduces the required pedal depres
-
sion force, particularly when the vehicle is heavily 
loaded or driven on road surfaces with high fric
-
tional coefficients.
•Because the duty placed on the front brakes is 
reduced, the increase in pad temperature can be 
controlled during brakes application to improve 
the wear resistance characteristics of the pad.
•Control valves such as the proportioning valve 
are not required.
SPECIFICATIONS
ItemSpecification
ABS control method4-sensor, 4-channel
Wheel speed 
sensorMagnetic encoderFront86 (N pole:43 S pole:43)
Rear86 (N pole:43 S pole:43)
Ty p eSemiconductor 

GENERAL INFORMATION
ANTI-SKID BRAKE SYSTEM (ABS)35B-3
CONSTRUCTION DIAGRAM
AC400129AB1
2
3, 7 1
4
5
6
Name of partNumberOutline of function
SensorWheel speed sensor1Sends alternating current signals at frequencies which are 
proportional to the rotation speeds of each wheel to the 
ABS-ECU.
Stop lamp switch2Sends a signal to the ABS-ECU to indicate whether the 
brake pedal is depressed or not.
ActuatorHydraulic unit3Drives the solenoid valves according to signals from the 
ABS-ECU in order to control the brake hydraulic pressure 
for each wheel.
ABS warning lamp4Illuminates in response to  signals from the ABS-ECU 
when a problem develops in the system.
Brake warning lamp5Illuminates in response to  signals from the ABS-ECU 
when a problem develops in the EBD system.
Diagnosis connector6Outputs the diagnosis codes and allows communication 
with the M.U.T.-III.
ABS-ECU7Controls actuators (described above) based on the signals 
coming from each sensor.
Controls the self-diagnosis and fail-safe functions.
Controls the diagnostic function (M.U.T.-III compatible). 

GENERAL INFORMATION
ANTI-SKID BRAKE SYSTEM (ABS)35B-4
SYSTEM CONFIGURATION DIAGRAM
AC314168
Stop lamp switch
Front-right wheel speed sensor Rear-right wheel speed sensor
Rear-left wheel speed sensor Front-left wheel speed sensor
ABS-ECU power supply Engine-CVT-ECU
Front-right solenoid valve (out)
Front-right solenoid valve (in)
Front-left solenoid valve (out)
Front-left solenoid valve (in)
Rear-right solenoid valve (out)
Rear-right solenoid valve (in)
Rear-left solenoid valve (out)
Rear-left solenoid valve (in)
ABS-ECU
Hydraulic
unit Rear-right 
wheel speed 
sensor
Front right 
wheel speed 
sensor
Front-left 
wheel speed 
sensor Rear-left 
wheel speed 
sensor
Front-right wheel (FR)
Front-left wheel (FL) Rear-right wheel (RR)
Rear-left wheel (RL)
Stop lamp switch
AB
Brake warning lamp
ABS warning lamp
Diagnosis connector
NO TE: Broken lines show CAN-bus lin e. 

GENERAL INFORMATION
ANTI-SKID BRAKE SYSTEM (ABS)35B-5
ABS ELECTRICAL CIRCUIT DIAGRAM
AC314169
Engine-CVT-ECU
Front wheel speed
sensor Rear wheel speed
sensor
Motor power
supply
Solenoid valve
power supply
ABS-ECU
Motor power
supply
Solenoid valve
Hydraulic unit
Stop lamp
switch J/B
(Fuse)
No.42
15A No.40
7.5A
Fusible
link No.1
Ignition
switch (IG1) Fusible
link No.5 Fusible
link No.3
J/B
(Fuse)
No.33
15A Fusible
link No.6
J/C
(CAN2)
J/C
(CAN1) Diagnosis connector
Combination meter
(ABS warning lamp and
 brake warning lamp)
AB
(rear, right)
(front, right)
(front, left)
(rear, left)
On
Off 

CONSTRUCTION DESCRIPTION
ANTI-SKID BRAKE SYSTEM (ABS)35B-6
CONSTRUCTION DESCRIPTION
SENSORSM2351001000427
WHEEL SPEED SENSORS AND MAG-
NETIC ENCODER FOR WHEEL SPEED 
DETECTION
AC601358
Rear wheel speed sensor
Front wheel speed sensor
Front Rear 
Encoder for wheel 
speed detection Encoder for wheel 
speed detectionRear wheel speed sensor
Encoder for wheel 
speed detection
AB
Wheel spee d se nsor  is a  kin d  of a  pulse gen erator 
consisted of 
a mag netic encoder  (a pla t e on which 
north an
d so uth po le sides of th e mag net are  
arrange
d alte rnately) for  wh eel speed  detection  
which rot
a tes at the same speed of the wheels, and a 
spee
d sen s or (semicon duct o r se nsor),  send s fre
-
quency pulse  sig nals in  proportion to  wh eel spee d.
Front wheel sp eed sensor co nsist s  of  a front whe e l 
spee
d sen s or secu red on  the knuckle,  and a  mag
-
netic encoder for wheel  spee d dete c tio n  fitt ed to th e 
inside o
f  the fro n t wheel  bearing. Rear  wh eel speed  
sensor consist
s  o f  a rear  wh eel speed  sensor 
secured on
 the re ar hub,  and a  magn etic encoder fo r 
whe
e l speed  detection  press fit t ed to  the rear  hub 
inner ring.
ABS-ECU
M23510030 0025 2
•By integrating  ABS-ECU into  the hydraulic unit ,  
no 
more  wiring h a rnesses for sending signal that  
ope
rates the solen o id valve an d pump mo tor is 
requ
ired,  assuring  high er reliability .
•Self-diag nostic p r ograms an d memory functions 
are 
integrated into ABS-ECU.  If any malfunction 
is dete
c ted  by th e se lf-diagnostic function,  
ABS-ECU activates 
a fail-s afe function and illumi
-
nates ABS warning lamp and brake warning 
la
mp
*.
NO TE: *: ABS-E CU illuminates the brake warning 
l
a
m
p  as  EBD c o nt ro l  wa rn in g  la m p .
•ABS-ECU detects  vehicle speed from the  wheel 
speed sensor signal, reco
gnizes  the whee l rot a
-
tion, estimates the wheel slip condition  based on 
the
 preprog rammed algorithm, a nd the n  co ntrols 
th
e soleno id  valve  in  the  hydr aulic u n it  so th at  the  
wheels d
o  not lock.
ABS FLUID PRESSURE CONTROL
FOUR-WHEEL CONTROL
ABS fluid pressure is controlled indep enden tly  for 
four whee
ls. 

CONSTRUCTION DESCRIPTION
ANTI-SKID BRAKE SYSTEM (ABS)35B-7
EBD FLUID PRESSURE CONTROL
AC208548AB
Ideal distribution curve when 
seated by fixed personsEBD operating conceptual design
Rear braking force
Ideal distribution curve when seated by one persons Braking force distribution curve 
by the existing proportioning valveBraking force distribution 
by EBD control
Front braking force
Braking Force 
Improved
EBD control is 
activate d within the lower slip  ratio 
area where
 ABS is disab l ed.  ABS-ECU calculates 
vehicle
 decelera t ion a nd slip  amou nt of th e four 
whe
e ls based on  the wheel  sp eed senso r  signal.  If 
the rear
 wh eel speed  dif f ers f r om th e ve hicle speed 
by a 
cert ain  level or  more,  ABS-ECU boost, holds,  
and de
pressurises  the rea r  wh eel contro l so leno id 
valve in the h
y drau lic unit, and  then a d just s rear 
whe
e l b r ake  fluid pressure  fa ir ly close to  an ideal dis
-
tribution curve.
INITIAL CHECK
ABS-ECU inter nally activates the self-d iagno stic 
function. ABS-ECU illuminates
 ABS  warning l a mp  for 
3 seconds (in
c lu ding  the in itia l check) 
* after th e ign i-
tion switch is turned  ON. If a n y malf unction is 
detected, ABS-ECU cont
inues illuminating ABS 
war
n ing  lamp and disables ABS cont rol.
NOTE: *: ABS warning lamp may st ay ON af ter the 
ignition 
switch is turned  ON un til t he st artu p ve hicle 
spee
d reaches  approximately 10km/h .  As far  as 
ABS-ECU memorizes  any d i agn osis code related t o  
the 
whee l  speed sen s or malfunct i on record ed  d u ring 
previous ignition ON st atus, ABS-ECU continues illu
-
mina ting  ABS warn ing lamp  until it verif i es that th e 
malfunct
i on  for tha t  co de is resolved (S t a rtup  che ck).  
STARTUP CHECK
When th e st artup  veh i cle sp eed re ache s app roxi-
mately 10 km/h, ABS-ECU performs the following 
checks.
•Motor,  solen o id valve check (onl y i n  ini t ial  st ar-
tup*)
Operat es  the motor relay in ECU  and checks  the 
pump motor op eratio n. At the  same time, 
ABS-ECU sequentially e nergizes each solenoid 
valve in a ve ry sh ort perio d and ch ecks the   valve 
ope ration .
NOTE: *: Initia l st artu p ind i ca tes a  first st artup  af ter 
the
 system has st arted .
•Whee l speed  sensor check
ABS-ECU che cks for a n y whee ls  that ha ve no t 
received whee l sp eed sens or signal from  the 
st artu p.
CONSTANT CHECK
ABS-ECU con s t antly ch ecks th e following  item.
•ABS-ECU
Performs se lf-diagnosis in ECU.
•ECU power supply
Checks if  ECU po we r sup p ly volt ag e reaches within  
the  operat ional range .
•Whee l speed  sensor
•Monitors the ou tput volt age  of the sensor sig-
nal wiring ha rness an d che c ks for a bnormal 
output
 volt ag e (ope n/sho r t circuit).
•Checks fo r any wheels tha t  do n o t send pu lse  
sig
nal while th e ve hicle is in  motion.
•Checks if wheel  spee d which is abno rmally 
high
er or lo we r than  the vehicle speed  is 
inpu
t.
•Pump mo tor and  solenoid  valve
Checks tha t  ABS-ECU outp u t signal and t he ope rat-
ing co ndition of  the pump motor an d so leno id 
valve agree
 with ea ch ot her . 

CONSTRUCTION DESCRIPTION
ANTI-SKID BRAKE SYSTEM (ABS)35B-8
CAN COMMUNICATION
ABS-ECU outputs ABS warning lamp and EBD 
warning lamp
* illumination request signals to the 
combination meter through CAN communication.
NOTE: *: ABS-ECU illuminates the brake warning 
lamp as EBD control warning lamp.
FAIL - SAFE FUNCTION
If any malfunction is detected by the self-diagnostic 
function, ABS-ECU illuminates ABS warning lamp 
and brake warning lamp
*, and it controls ABS and 
EBD as shown in the following table.
NOTE: *: ABS-ECU illuminates the brake warning 
lamp as EBD control warning lamp.
Diagnosis 
code No.ItemAction during fail-safe operation
ABS controlEBD controlCAN outputBrake 
warning 
lampABS 
warning 
lamp
C1200Open or short 
circuit in wheel 
speed sensor (FR)Prohibits 
control of 
malfunctioning 
wheel. 
Prohibits all 
wheel control 
after control is 
completed.Two or less 
wheel 
Abnormal: 
Enabled
Three or 
more wheels 
Abnormal: 
Prohibits
Output 
permittedTw o o r  l es s  
wheel 
Abnormal: 
OFF
Three or 
more 
wheels 
Abnormal: 
ON
ON
C1201Wheel speed 
sensor (FR) system
C1205Open or short 
circuit in wheel 
speed sensor (FL)
C1206Wheel speed 
sensor (FL) system
C1210Open or short 
circuit in wheel 
speed sensor (RR)
C1211Wheel speed 
sensor (RR) 
system
C1215Open or short 
circuit in wheel 
speed sensor (RL)
C1216Wheel speed 
sensor (RL) system
C1225Wheel speed 
sensor malfunctionSystem 
shut-downSystem 
shut-downOutput 
permittedONON 

CONSTRUCTION DESCRIPTION
ANTI-SKID BRAKE SYSTEM (ABS)35B-11
SERVICE DATA OUTPUT
The following items of the ECU input data can be 
read using M.U.T.-III.
Item No.Check itemCheck conditionNormal condition
01FR wheel speed sensorPerform a test run of the vehicle.Speedometer display and 
M.U.T.-III display almost agree 
with each other.
02FL wheel speed sensor
03RR wheel speed sensor
04RL wheel speed sensor
05Power supply voltageAlways10 V or more
06Stop lamp switchThe brake pedal is depressedON
The brake pedal is released.OFF
07Va l v e  r e l a yWhen ABS is operatingON
When ABS is not operatingOFF
10FL inlet valve When ABS is operatingON
When ABS is not operatingOFF
11FL outlet valve When ABS is operatingON
When ABS is not operatingOFF
12FR inlet valve When ABS is operatingON
When ABS is not operatingOFF
13FR outlet valve When ABS is operatingON
When ABS is not operatingOFF
14RL inlet valve When ABS is operatingON
When ABS is not operatingOFF
15RL outlet valve When ABS is operatingON
When ABS is not operatingOFF
16RR inlet valve When ABS is operatingON
When ABS is not operatingOFF
17RR outlet valve When ABS is operatingON
When ABS is not operatingOFF
20Pump motorWhen ABS is operatingON
When ABS is not operatingOFF