sensor ACURA RL KA9 1996 Service Repair Manual

Wheel Spee d an d Modulato r Contro l
SPEED VEHICL E SPEE D
REFERENC E VEHICL E SPEE D
PRESSUR E
OUTLETVALVE
INLETVALV E
MOTO R
ON
OF F
WHEE L SPEE D
TIM E
Whe n th e whee l spee d drop s sharpl y belo w th e vehicl e speed , th e inle t valv e close s t o retai n th e calipe r flui d pressure .
Whe n th e whee l spee d drop s further , th e outle t valv e open s momentaril y t o reduc e th e calipe r flui d pressure . Th e pum p
moto r start s a t thi s time .
A s th e whee l spee d i s restored , th e inle t valv e open s momentaril y t o increas e th e calipe r flui d pressure .
Whee l Senso r
Th e whee l sensor s ar e th e magneti c contactles s type . A s th e gea r pulse r teet h rotat e pas t th e whee l sensor' s magnetic
coil , A C curren t i s generated . Th e A C frequenc y change s i n accordanc e wit h th e whee l speed . Th e AB S contro l uni t detect s
th e whee l senso r signa l frequenc y an d thereb y detect s th e whee l speed .
GEAR PULSE R
WHEEL SENSO R a
t HIG H SPEE D
at LO W SPEE D
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Troubleshooting
DTC 11 , 13 , 15 , 17 : Whee l Senso r (Open/Shor t t o Bod y Ground/Shor t t o Power )
With th e ignitio n switc h O N
(II) , th e AB S indicato r doe s
not g o off .With th e SC S servic e connec -
to r connecte d (se e pag e
19-119 ), DTC s 11 , 13 , 15 , 1 7 ar e
indicated .
Chec k fo r a shor t t o powe r i n th e
whee l senso r circuit :
1 . Disconnec t th e AB S contro l
unit 22 P connector .2. Star t th e engine .
3 . Measur e th e voltag e betwee n
th e appropriat e whee l senso r
(+) circui t termina l an d bod ygroun d (se e table) .
DTC
11 (Right-front )
13 (Left-front )
15 (Right-rear )
17 (Left-rear )
Appropriat e Termina l
(+) Sid e
No. 9 : FR W (+)
No . 7 : FL W (+ )
No . 19 : RR W (+ )
No . 17:RLW(+ )
(-) Sid e
No. 8 : FR W (-)
No . 6 : FL W (-)
No . 20 : RR W (-)
No . 18 : RL W (-)
Is ther e 2 V or more ?
NOTE : Judgemen t valu e fo r shor t t o
powe r i s 2 V . Repai
r shor t t o powe r i n th e (+ )
circui t wir e betwee n th e AB S
contro l uni t an d th e appropriat e
whee l sensor .
Chec k fo r a shor t t o bod y groun d
i n th e whee l senso r circuit :
Check fo r continuit y betwee n th eappropriat e whee l senso r (+ ) cir -cuit termina l an d bod y groun d(see table) .
I s ther e continuity ?
Chec k fo r a n ope n i n th e whee l
senso r circuit :
Chec k th e resistanc e betwee n th e
appropriat e whee l senso r (+ ) an d
(-) circui t terminal s (se e table) .
Is th e resistanc e OK ?Front/Rear : 45 0 - 2,05 0
(a t 20°C , 68°F) .
Check fo r loos e AB S contro l uni tconnectors , i f necessary , substi -tute a known-goo d AB S contro lunit an d recheck . Repai
r shor t t o bod y groun d in
th e (+ ) o r (- ) circui t wir e betwee n
the AB S contro l uni t an d th eappropriat e whee l sensor .
Replac e th e appropriat e whee l
sensor .
Repair ope n i n the (+) o r (- )
circui t wire , o r shor t t o th e (+ )
circui t wir e i n th e (- ) circui t
wir e betwee n th e AB S contro l
uni t an d th e appropriat e whee l
sensor .
Replac e th e appropriat e whee l
sensor . AB
S CONTRO L UNI T 22 P CONNECTO R
Wir e sid e o f femal e terminal s
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DTC 12 , 14 , 16 , 18 : Whee l Senso r (Electrica l Noise/Intermitten t Interruption )
Are the y installe d correctly ?
Chec k fo r a shor t t o wir e i n th e
on e whee l senso r circuit :
1 . Disconnec t th e AB S contro l
uni t 22 P connector .
2 . Measur e th e resistanc e
between th e appropriat ewheel senso r (+ ) an d (- ) cir -
cui t terminal s (se e table) .
I s ther e les s tha n 45 0 Q ?
Chec k fo r a shor t t o anothe r wir e
i n th e whee l senso r circuits :
Chec k fo r continuit y betwee n th e
appropriat e whee l senso r (+ ) cir -
cuit termina l an d othe r whee lsensor (+ ) circui t terminal s (se e
table) .
Is ther e continuity ? NOTE
: I f th e AB S indicato r come s o n fo r th e reason s describe d below , th e indicato r
shoul d g o of f whe n yo u test-driv e th e vehicl e a t speed s abov e 1 9 mp h (3 0 km/h) .
• Onl y th e driv e wheel s rotate d• Th e vehicl e spu n
• Electrica l nois e
DTC
12
1 4
16
18
Appropriat e Whee l Senso r
Right -fron t
Left - fron t
Right - rea r
Lef t - rea r
Reinstal l o r replac e th e appropri -
at e whee l senso r o r pulser .
DTC
12 (Right-front )
1 4 (Left-front )
1 6 (Right-rear )
1 8 (Left-rear )
Appropriat e Termina l
(+) Sid e
No. 9 : FR W (+ )
No . 7 : FL W (+ )
No . 19 : RR W (+ )
No . 17 : RL W (+ )
(-) Sid e
No. 8 : FR W (-)
No . 6 : FL W (-)
No . 20 : RR W <- )
No . 18 : RL W (-)
Repai r shor t t o wir e betwee n th e
appropriat e whee l senso r (+ ) an d
(- ) circuits .
DTC
12 (Right-front )
14 (Left-front )
16 (Right-rear )
18 (Left-rear )Appropriat
e
Termina l
No. 9 : FR W (+ )
No . 7 : FL W (+ )
No . 19 : RR W (+ )
No . 17 : RL W (+ )
Othe r Termina l
No. 7 : FL W (+ )
No . 9 : FR W (+ )
No . 9 : FR W (+ )
No . 9 : FR W (+ )
No . 19 : RR W (+ )
No . 19 : RR W (+ )
No . 7 : FL W (+ )
No . 7 : FL W (+ )
No . 17 : RL W (+ )
No . 17 : RL W (+ )
No . 17 : RL W (+ )
No . 19 : RR W (+ )
Repai r shor t t o wir e betwee n th e
appropriat e whee l senso r an d
th e othe r whee l sensor .
Wit
h th e ignitio n switc h O N
(II) , th e AB S indicato r doe s
not g o off .With th e SC S servic e connec -
to r connecte d (se e pag e
19-119 ), DTC s 12 , 14 , 16 , o r 1 8are indicated .
Visually chec k fo r appropriat ewheel senso r an d pulse r installa -
tio n (se e table) .
Eras e th e DT C an d test-driv e th e
vehicle . I f AB S indicato r conie s
o n an d sam e DT C is indicated ,
replac e th e AB S contro l unit .
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ABS Contro l Uni tPulsers/Whee l Sensor s
Removal/Installatio n
1. Remov e th e glov e box .
2 . Remov e th e glov e bo x bac k cover .
3 . Remov e th e righ t fron t doo r trim .
4. Remov e th e righ t kic k panel .
5. Tur n u p th e floo r mat .
6 . Remov e th e PC M cover .
7. Remov e th e connector s insid e o f th e righ t kic k
panel .
8 . Remov e th e harnes s cli p A for m th e AB S contro l
unit, the n remov e th e bol t a t lowe r sid e o f th e AB S
contro l unit .
9. Remov e th e multiple x contro l uni t (passenger&#39;s) .
10 . Remov e th e harnes s cli p B an d C .
11 . Remov e th e bol t a t rea r o f th e AB S contro l unit ,
the n pul l ou t th e AB S contro l unit .
HARNES S CLI P BCONNECTOR S(Inside th e
righ t kic k panel. )
AB S CONTRO L UNI T
HARNES SCLIP AHARNES S CLI P C
MULTIPLE X CONTRO LUNIT (PASSENGER&#39;S )
12. Instal l th e AB S contro l uni t i n th e revers e orde r o f
removal .
Inspectio n
1. Chec k th e fron t an d rea r pulse r fo r chippe d o r dam -
age d teeth .
2 . Measur e th e ai r ga p betwee n th e whee l senso r an d
pulse r al l th e wa y aroun d whil e rotatin g th e pulser .
I f th e ga p exceed s 1. 0 m m (0.0 4 in) , chec k fo r a ben t
suspensio n arm .
Rear
Remov e th e rea r brak e dis c t o inspec t th e rea r whee l
senso r ai r gap .
Fron t
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Wheel Sensor Replacement

Install the sensors carefully to avoid twisting wires.

Front

6 mm BOLT

9.8 N-m (1.0 kgf-m, 7.2 Ibf-ft)

WHEEL SENSOR

Rear

6 mm BOLT

9.8 N-m (1.0 kgf-m, 7.2 Ibf-ft)

WHEEL SENSORProCarManuals.com

Component Locations

SERVICE CHECK CONNECTOR (2P)

ABS CONTROL UNIT

ECT SENSOR

TCS CONTROL VALVE

SENSOR

RIGHT-FRONT

WHEEL SENSOR

TCS CONTROL

VALVE ACTUATOR
LEFT-REAR

WHEEL SENSOR

GAUGE ASSEMBLY

ECU (PCM) (20 A) FUSE

UNDER-HOOD FUSE/RELAY BOX

BATTERY (120 A) FUSE
UNDER-HOOD RELAY BOX C

FAIL-SAFE RELAY

IG SW (50 A) FUSE

METER (15 A) FUSE
METER RELAY
TCS (15 A) FUSE
STOP/HORN

&#39;96 - 98 models: (15 A) FUSE

&#39;99 model: (20 A) FUSE
UNDER-HOOD FUSE/RELAY BOX
UNDER-HOOD RELAY BOX C

LEFT-FRONT WHEEL SENSOR
POWERTRAIN

CONTROL MODULE (PCM)
STEERING ANGLE SENSOR

RIGHT-REAR WHEEL SENSOR

TCS CONTROL UNIT

TCS/CRUISE SWITCH

UNDER-DASH FUSE/RELAY BOX

UNDER-DASH FUSE/RELAY BOX

METER (7.5 A) FUSE

TCS INDICATOR LIGHTProCarManuals.com

System Description

Outline

Role of System

The traction control is a variable system designed to enhance traction during acceleration and cornering. It does so by

determining the optimum amount of wheel spin for any given driving situation, then suppressing surplus engine power

accordingly.

Construction and Function

The TCS control unit gets signals about the vehicle&#39;s speed, direction, and road conditions from sensors at the wheels and

the steering column. Based on these signals, the control unit will determine the optimum amount of wheel spin. Because

the system is variable, the control unit may determine, depending on the driving conditions, that some wheel spin is bene-

ficial (thus enhancing straight-line acceleration), or that no wheel spin is beneficial (thus enhancing cornering). For any

given driving situation, the control unit will determine the amount of wheel spin best suited to the driver&#39;s needs and, if

necessary, will then signal the TCS control valve actuator and Powertrain Control Module (PCM) to reduce engine power.

The system is automatically &#34;ready&#34; whenever the engine is started, but can be manually canceled with the TCS switch.

However, once activated, the system cannot be canceled until it is once again in the ready state.

Components:

Wheel sensors: The TCS &#34;shares&#34; the wheel sensors with the ABS. The wheel sensors transmit wheel speed signals to

the TCS through the ABS control unit.

Steering angle sensor: The steering angle sensor signals the TCS control unit about the amount of steering angle.

TCS control valve sensor: The TCS control valve sensor signals the TCS control unit about the amount of TCS control

valve angle.

TCS control valve actuator: The actuator gets signals from the TCS control unit and closes the TCS control valve

accordingly.

TCS control unit: The TCS control unit detects the driving condition signals from the sensors and, if necessary, signals

the Powertrain Control Module (PCM).ProCarManuals.com

Construction and Function

TCS Control unit

Driving Control

When the drive wheel speed exceeds the vehicle speed by a given amount, the TCS control unit judges that the drive

wheels are slipping, and it outputs the traction control signal to reduce engine power.

Handling Control

Based on signals about right and left driven wheel rotational speeds, the control unit calculates the vehicle&#39;s &#34;yaw&#34; rate

(the turn rate of the vehicle&#39;s body). Based on signals from the steering angle sensor, the control unit also calculates the

yaw rate expected by the driver. If the difference between actual and expected yaw rates is substantial — that is, if the

direction of the vehicle&#39;s body will exceed the driver&#39;s expected line — the control unit signals the TCS control valve actu-

ator and PCM, thus reducing engine power and maintaining the expected line.

Rough Road Control

Based on signals from the wheel sensors, the control unit detects a rough road based on frequency of wheel rotational

vibration. The control unit then signals the TCS control valve actuator and PCM to relax engine power, thus improving

acceleration efficiency.

Grip Control

Based on signals about wheel speed and yaw rate, the control unit determines the efficiency of the grip of the tires on the

road and signals the TCS control valve actuator and PCM to relax engine power if necessary, thus improving grip.

Main Control BlockProCarManuals.com

System Descriptio n
Fail-Safe Functio n
I f th e contro l uni t detect s a n abnormality , i t shut s th e
tractio n contro l syste m of f an d cause s th e TC S indicato r
light t o com e on . Howeve r i f th e abnormalit y is detecte d
while th e TC S is activated , th e contro l uni t firs t estab -
lishe s th e appropriat e whee l spi n velocity , the n shut s
the syste m down , thu s preventin g excessiv e whee l spin .
Self-Diagnosi s Functio n
If th e contro l uni t detect s a n abnormality , i t record s a
Diagnosti c Troubl e Cod e (DTC ) whic h ca n b e use d t o
diagnos e th e problem . Th e DT C is show n a t th e TC S
indicato r ligh t whe n th e Servic e Chec k connecto r termi -
nal s ar e connecte d wit h th e SC S servic e connector .
Steerin g Angl e Detectio n
Steerin g angl e is detecte d b y th e steerin g angl e sensor .
A dis c wit h a regula r patter n o f slit s is positione d betwee n
th e facin g part s o f a ligh t emittin g par t (LED) , an d a ligh t
receivin g par t (phot o transistor) . As the dis c rotates , i t
interrupt s th e ligh t fro m th e LED . Th e ligh t whic h passe s
throug h a sli t i s converte d int o th e electri c curren t b y th e
phot o transistor , an d th e wavefor m o f thi s electri c cur -
ren t i s shape d b y th e comparato r t o outpu t th e dis c rota -
tio n a s a rectangula r signal .
Th e analysi s performanc e o f th e syste m is improve d b y
providin g th e fixe d sli t i n fron t o f th e LED , an d thereb y
identifyin g th e brightnes s an d darknes s o f th e ligh t whic h
i s receive d a t th e phot o transistor .
Th e outpu t signa l i s a 2-phas e outpu t (A-phas e an d Bi -
phase) , an d th e steerin g whee l turnin g angl e an d th e
turnin g directio n ar e calculate d b y th e TC S contro l unit .
Vehicl e Spee d Detectio n
Whee l rotatio n spee d i s detecte d b y th e whee l sensors ,
locate d a t eac h wheel . Th e signal s ar e sen t t o th e con -
trol unit , whic h compare s eac h wheel&#39; s spee d an d deter -
mines whethe r tractio n contro l i s required .
FIXED SLI T
LIGH T EMITTIN G PAR T (LED )
TCS INDICATO R LIGH T
LIGHT RECEIVIN G PAR T(PHOT O TRANSISTOR )
SLIT
Steerin g whee l i s
turne d to right .
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Engine Output Control

When the TCS is activated, the TCS control unit signals the TCS control valve actuator and PCM. The actuator is linked to

the TCS control valve which is normally returned to the fully open position by the two return springs. Although the throttle

valve is still within the driver&#39;s control, the engine output is relaxed by the TCS control valve and PCM to achieve optimum

traction.

TCS CONTROL VALVE SENSOR

TCS CONTROL VALVE
TCS CONTROL VALVE

RETURN SPRINGS

TCS CONTROL VALVE

ACTUATOR (DC MOTOR)

DURING NORMAL DRIVING:
DURING TCS ACTUATION:

TCS CONTROL VALVE

TCS CONTROL VALVE

ACTUATOR (DC MOTOR)
TCS CONTROL VALVE

RETURN SPRINGS

TCS ACTUATION SIGNAL

FROM TCS CONTROL UNITProCarManuals.com