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' 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'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
TCS Control Unit Terminal Arrangement
TCS CONTROL UNIT 14P CONNECTOR
Wire side of female terminals
VB: Battery Voltage
Terminal
number
1
2
3
4
5
6
7
8
9
10
11
12
13
14
Wire
color
WHT/GRN
BLU/GRY
WHT/RED
BRN/BLK
GRY/BLK
RED
GRY/WHT
LT
GRN/RED
GRY
PNK/BLK
WHT/BLK
BLU/WHT
BRN/YEL
RED/BLK
Terminal sign
(Terminal name)
FRP
(Front right pulse)
WARN1
(Warning 1)
FLP
(Front left pulse)
LG1
(Logic ground 1)
RRP
(Rear right pulse)
TCV
( traction
control valve)
RLP
(Rear left pulse)
TC-INH
(Traction control
inhibit)
STR-B
(Steering B)
TC-STB
(Traction control
standby)
TC-SW
(Traction control
switch)
VREF
(Voltage
reference)
STR-A
(Steering A)
TPS
(Throttle posi-
tion sensor)
Description
Detects right-front
wheel sensor signal
Drives TCS indicator
light (The indicator light
comes on by the
self-bias)
Detects left-front wheel
sensor signal
Ground for the logic
circuit
Detects right-rear wheel
sensor signal
Detects TCS control
valve sensor signal
Detects left-rear wheel
sensor signal
Fl TCS, TCS opera-
tion permission signal
Detects steering angle
sensor signal B
TCS Fl, TCS opera-
tion start signal
Detects TCS switch
signal
Reference voltage for
the sensors of the
PGM-FI system
Detects steering angle
sensor signal A
Detects throttle position
sensor signal
Voltage
Measurement
terminals
1-GND
2-GND
3-GND
4-GND
5-GND
6-GND
7-GND
8-GND
9-GND
10-GND
11-GND
12-GND
13-GND
14-GND
Conditions
(Ignition Switch ON (ID)
Rotate the right-front
wheel.
Indicator light ON
Indicator light OFF
Rotate the left-front
wheel.
Rotate the right-rear
wheel.
TCS control valve is
fully closed.
TCS control valve is
fully open.
Rotate the right-rear
wheel.
Permission (normal)
Inhibition (the coolant
temperature is 0°C or
below)
Failure (TCS and/or
PCM is failure)
Rotate the steering
wheel.
TCS is functioning.
TCS is not functioning.
Push the TCS switch.
Release the TCS switch.
Rotate the steering
wheel.
Throttle valve is fully
closed.
Throttle valve is fully
open.
Output
voltage
About 2.5 V
About 2 V
VB
About 2.5 V
Below 0.3 V
About 2.5 V
About 0.5V
About 4.5 V
About 2.5 V
About 2.5V
(5 V. Duty 50)
About 5 V
About 0 V
5V 0V
0V
About 5 V
VB
0V
About 5 V
5V 0V
About 0.5 V
About 4.5 VProCarManuals.com
TCS CONTROL UNIT 20P CONNECTOR
Wire side of female terminals
VB: Battery Voltage
Terminal
number
1
2
4
5
6
9
10
11
12
13
14
15
16
17
20
Wire
color
BLK/YEL
GRN/RED
BLU
PNK/BLU
BLK/WHT
BLK
BRN/WHT
GRN/WHT
BLU
GRN/ORN
BLK/ORN
BRN/BLK
WHT/BLU
BLU/GRY
GRN
BRN
Terminal sign
(Terminal name)
IG1
(Ignition 1)
PARK
(Parking)
SCS
(Service check
signal)
STR-GND
(Steering ground)
AT-SHIFT
(AT shift)
FSR
(Fail-safe relay)
PMG
(Power motor
Ground)
VPM
(Voltage power
motor)
STOP
(Stop)
NEP (Engine
speed pulse)
BARO
(Barometric)
TC-FC
(Traction control
fuel cut)
LG2
(Logic ground 2)
STR-VCC (Steer-
ing power supply)
WARN2
(Warning 2)
SH-MOT
(Shield motor)
MOT +
(Motor +)
MOT-
(Motor -)
Description
Detects ignition switch
IG1 signal
Detects parking brake
switch signal
Detects service check
connector signal
(Diagnostic trouble
code indication)
Ground for the steering
angle sensor
Detects A/T shift posi-
tion signal
Drives fail-safe relay
Power ground for the
TCS control valve
actuator motor
Power source for the
TCS control valve
actuator motor
Detects brake pedal
position switch signal
Detects engine speed
signal
Detects barometric
sensor signal
TCS Fl, Fuel cut
(torque down) signal
Ground for the logic
circuit
Power source for the
steering angle sensor
Drives TCS indicator light
(The indicator light comes
on by the self-bias)
Shield for the TCS con-
trol valve actuator motor
Drives TCS control
valve actuator motor
Drives TCS control
valve actuator motor
Measurement
terminals
1-GND
2
3-GND
4-GND
5-GND
6-GND
9-GND
10-GND
11-GND
12-GND
13-GND
14-GND
15-GND
16-GND
17-GND
19-20
20-19
Voltage
Conditions
(Ignition Switch ON (II))
Depress the parking
brake pedal.
Release the parking
brake pedal.
SCS service connector
connected.
SCS service connector
disconnected.
Shift the transmission
to position, then
start the engine.
Start the engine.
Start the engine.
Brake pedal depressed.
Brake pedal released.
Engine idling
TCS is functioning,
(maximum fuel cut)
TCS is not functioning.
Indicator light ON
Indicator light OFF
TCS is functioning.
TCS is not functioning.
TCS is functioning.
TCS is not functioning.
Output
voltage
VB
Below 0.6 V
VB
0V
5V
Below 0.3V
About 4V
(5V 0V)
VB
1.5V
Below 0.3 V
0V
VB
VB
0V
About 6V
(12V
0V)
About 3 V
About 1.5V
About 4.5 V
(5 V,
PWM)
Below 0.3V
About 5 V
About 2 V
VB
VB
0V
VB
0VProCarManuals.com
Troubleshooting Precautions
1. In any of these cases, the TCS indicator light may come on or stay on even the TCS system is normal.
The coolant temperature is 32°F (0°C) or below.
The parking brake is applied for more than 30 seconds while the vehicle is being driven.
The tires are not inflated to the specified pressure.
The wheel sensor signal is interrupted during driving at speeds of 6 mph (10 km/h) or above due to, for example, a
vehicle spinning.
The MAP sensor, the coolant temperature sensor, the ICM or the atmospheric pressure sensor system of the PGM-FI
system is faulty.
2. TCS does not function when the TCS indicator light is ON.
3. When both the TCS indicator light and the MIL are ON, troubleshoot the PGM-FI system first.
4. When both the TCS indicator light and the ABS indicator light are ON, troubleshoot the ABS first.
5. The DTC 4-9 (ABS down) is memorized when the ABS control unit cannot output the wheel speed signal due to, for
example, a missing or blown ABS B2 (15 A) fuse. If you fail to erase the DTC of the TCS after troubleshooting the ABS,
the DTC remains in the TCS control unit memory. Therefore, be sure to test-drive the vehicle, and check the TCS indica-
tor light before starting to troubleshoot the TCS.ProCarManuals.com
Troubleshooting
Steering Angl e Senso r
Diagnosti c Troubl e Cod e (DTC ) 2-1 : Steerin g Angl e Senso r Diagnosi s
The TC S contro l uni t perform s th e self-diagnosi s fo r th e steerin g angl e senso r whe n th e spee d o f th e fou r wheel s exceed s
6 mp h (1 0 km/h ) o n a smoot h road . Th e TC S indicato r ligh t come s o n if a ya w rat e is generated , th e correspondin g steer -
ing angl e signa l i s no t inpu t whe n th e steerin g whee l i s turned , an d ther e is n o inpu t fro m th e STO P (brak e peda l positio n
switch signal ) an d PAR K (parkin g brak e switc h signal) .
With engin e running , TC S indi -
cato r ligh t i s ON .
Th e tir e pressur e i s correct ,
an d tire s wit h a correc t diame -
te r ar e installed .
Wit h th e SC S servic e connec -
to r connecte d (se e pag e
19-159 ), DT C 2- 1 is indicated .
Chec k fo r a shor t t o bod y groun d
i n th e wire s betwee n th e TC S con -
tro l uni t an d steerin g angl e sensor :
1 . Disconnec t th e TC S contro l uni t
14P an d 20 P connector s an dsteerin g angl e senso r connec -tor.2. Chec k fo r continuit y betwee n
bod y groun d an d TC S contro l
unit 14 P connecto r terminal sNo. 9 an d No . 1 3 individuall yand betwee n th e 20 P connec -
to r termina l No . 4 an d No . 1 6
individually .
Is ther e continuity ?
Chec k th e STR-VC C circui t insid e
th e TC S contro l unit :
1 . Connec t th e TC S contro l uni t
14 P an d 20 P connectors .
2 . Tur n th e ignitio n switc h O N (II) .
3. Measur e th e voltag e betwee nthe TC S contro l uni t 20 P con -necto r termina l No . 1 6 an dbod y ground .
Is ther e abou t 5 V ?
Chec k th e STR-GN D circui t insid e
th e TC S contro l unit :
Measur e th e voltag e betwee n th e
TC S contro l uni t 20 P connecto r ter -
mina l No . 4 an d No . 16 .
Is ther e abou t 5 V ?
T o pag e 19-16 9 TC
S CONTRO L UNI T 14 P CONNECTO R
Wir e sid e o f femal e terminal s
TC S CONTRO L UNI T 20 P CONNECTO R
Repair shor t t o bod y groun d in th ewire(s ) betwee n th e TC S contro l
uni t an d steerin g angl e sensor . Wir
e sid e o f femal e terminal s
Replac e th e TC S contro l unit .
Replac e th e TC S contro l unit .
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From pag e 19-16 8
Chec k fo r a n ope n in th e STR-VC C
circuit :
Measur e th e voltag e betwee n th e
steerin g angl e senso r connecto r
terminal No . 5 an d bod y ground .
Is ther e abou t 5 V ?
Chec k fo r a n ope n i n the STR -
GN D circuit :
Measur e th e voltag e betwee n th e
steerin g angl e senso r connecto r
terminals No . 5 an d No . 1 .
Is ther e abou t 5 V ?
Chec k th e STR- A circui t insid e th e
steerin g angl e sensor :
1. Tur n th e ignitio n switc h OFF .2. Connec t th e steerin g angl e sen -
so r connector .
3. Tur n th e ignitio n switc h O N (II) .4. Measur e th e voltag e betwee n
th e steerin g angl e senso r con -
necto r termina l No . 2 an d bod y
groun d whe n turnin g th e steer -
ing whee l slowly .
Is ther e 5 V 0 V ?
Chec k th e STR- B circui t insid e
th e steerin g angl e sensor :
Measur e th e voltag e betwee n th e
steerin g angl e sensor connecto r
terminal No . 4 an d bod y groun dwhen turnin g th e steerin g whee lslowly.
Is ther e 5 V 0 V ?
T o pag e 19-17 0 STEERIN
G ANGL E SENSO R CONNECTO R
Repai r ope n in th e wir e betwee n
th e TC S contro l uni t an d steerin g
angl e sensor . Wir
e sid e o f femal e terminal s
Repai r ope n i n th e wir e betwee n
th e TC S contro l uni t an d steerin g
angl e sensor .
Replac e th e steerin g angl e sensor .
Replac e th e steerin g angl e sensor .
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Troubleshooting
Steering Angl e Senso r (cont'd )
From pag e 19-16 9
Chec k fo r a n ope n i n th e STR- Acircuit:Measur e th e voltag e betwee n th e
TC S contro l uni t 14 P connecto r
termina l No . 1 3 an d bod y groun d
whe n turnin g th e steerin g whee l
slowly.
Is ther e 5 V 0 V?
Chec k fo r a n ope n in th e STR- B cir -
cuit :Measur e th e voltag e betwee n th e
TC S contro l uni t 14 P connecto r
termina l No . 9 an d bod y groun d
when turnin g th e steerin g whee lslowly .
Is ther e 5 V 0 V? Repai
r ope n in th e wir e betwee n
th e TC S contro l uni t an d steerin g
angl e sensor .
Wire sid e o f femal e terminal s
Repai r ope n in th e wir e betwee n
th e TC S contro l uni t an d steerin gangle sensor .
Erase th e DTC , an d tur n th e steer -
in g whee l slowl y afte r startin g
th e engine . I f TC S indicato r ligh t
come s o n an d DT C 2- 1 is indicated ,
replac e th e TC S contro l unit . TC
S CONTRO L UNI T 14 P CONNECTO R
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