1995 ACURA TL engine

Troubleshooting Precautions

ABS Indicator Light

1. If the system is OK, the ABS indicator light goes off two seconds after turning the ignition switch ON (II) without start-

ing the engine. After starting the engine, the ABS indicator light comes on again and goes off after two seconds. This

occurs because the ABS control unit is activated by the IG2 power source.

2. The ABS indicator light comes on when the ABS control unit detects a problem in the system. However, even though

the system is normal, the ABS indicator light comes on, too, under the following conditions. To determine the actual

cause of problem, question the customer about the problem, talking the following conditions into consideration.

Only drive wheels rotate

One wheel stuck of drive wheels

Vehicle spin

ABS operate condition continue for long time

Signal disturbance

3. When a problem is detected and the ABS indicator light comes on, there are cases when the indicator light stays on

until the ignition switch is turned OFF, and cases when the indicator light goes off automatically when the system

returns normal. For the DTC 61 and 62, the indicator light goes off automatically when the system returns normal. For

all other codes, the indicator light stays on until the ignition switch is turned OFF.

4. For DTCs 12, 14, 16, 18, 21, 22, 23, 24, 51, 52 and 53, the indicator light goes off when the vehicle is driven again and

the signals are OK after the ignition switch is turned from OFF to ON (II). However, if the DTC is erased, the CPU is

reset and the indicator light goes off right after the engine is started if the signals are OK.

Diagnostic Trouble Code (DTC)

1. The DTC is not memorized if the CPU cannot be activated or the CPU fails and the indicator light comes on.

2. The memory can hold any number of DTCs. However, when the same DTC is detected more than once, the later one

is written over the old one. Therefore, when the same problem is detected repeatedly, it is memorized as one DTC.

3. The DTCs are indicated in the order of ascending number, not in the order they occur.

4. The DTCs are memorized in the EEPROM (non-volatile memory). Therefore, the memorized DTCs cannot be canceled

by disconnecting the battery. Perform the specified procedures to erase the DTCs.

Self-diagnosis

1. The
self-diagnosis
can be
classified
into
two
categories.

• Initial diagnosis: Performed right after the engine starts and until the ABS indicator light goes off.

• Regular diagnosis: Performed right after the initial diagnosis until the ignition switch is turned OFF.

2. When a problem is detected by self-diagnosis, the system

• Turns the ABS indicator light ON

• Memorizes the DTC

• Turns the fail-safe relay OFF

• Stops ABS controlProCarManuals.com

System Descriptio n
Outline
Role o f Syste m
Th e tractio n contro l i s a variabl e syste m designe d t o enhanc e tractio n durin g acceleratio n an d cornering . I t doe s s o b y
determinin g th e optimu m amoun t o f whee l spi n fo r an y give n drivin g situation , the n suppressin g surplu s engin e powe r
accordingly .
Constructio n an d Functio n
The TC S contro l uni t get s signal s abou t th e vehicle' s speed , direction , an d roa d condition s fro m sensor s a t th e wheel s an d
the steerin g column . Base d o n thes e signals , th e contro l uni t wil l determin e th e optimu m amoun t o f whee l spin . Becaus e
th e syste m is variable , th e contro l uni t ma y determine , dependin g o n th e drivin g conditions , tha t som e whee l spi n i s bene -
ficia l (thu s enhancin g straight-lin e acceleration) , o r tha t n o whee l spi n i s beneficia l (thu s enhancin g cornering) . Fo r an y
give n drivin g situation , th e contro l uni t wil l determin e th e amoun t o f whee l spi n bes t suite d t o th e driver' s need s and , i f
necessary , wil l the n signa l th e TC S contro l valv e actuato r an d Powertrai n Contro l Modul e (PCM ) t o reduc e engin e power .
Th e syste m is automaticall y "ready " wheneve r th e engine is started , bu t ca n b e manuall y cancele d wit h th e TC S switch .
However , onc e activated , th e syste m canno t b e cancele d unti l i t i s onc e agai n i n th e read y state .
SERVIC E CHEC K CONNECTO R (2P )ABS CONTRO L UNI TTCS CONTRO L UNI TUNDER-DAS H RELA Y BO X
POWERTRAI N
CONTRO L MODUL E (PCM )
EC T SENSO R
TC S CONTRO L VALV E
ANGL E SENSO R STEERIN
G ANGL E SENSO R
RIGHT-REA R WHEE L SENSO R
RIGHT-FRON T
WHEE L SENSO R
Components :
• Whee l sensors : Th e TC S "shares " th e whee l sensor s wit h th e ABS . Th e whee l sensor s transmi t whee l spee d signal s t o
th e TC S throug h th e AB S contro l unit .
• Steerin g angl e sensor : Th e steerin g angl e senso r signal s th e TC S contro l uni t abou t th e amoun t o f steerin g angle .
• TC S contro l valv e sensor : Th e TC S contro l valv e senso r signal s th e TC S contro l uni t abou t th e amoun t o f TC S contro l
valv e angle .
• TC S contro l valv e actuator : Th e actuato r get s signal s fro m th e TC S contro l uni t an d close s th e TC S contro l valv e
accordingly .
• TC S contro l unit : Th e TC S contro l uni t detect s th e drivin g conditio n signal s fro m th e sensor s and , i f necessary , signal s
th e Powertrai n Contro l Modul e (PCM) .
LEFT-REA RWHEEL SENSO R
UNDER-HOO D FUSE/RELA Y BO X
LEFT-FRON
T WHEE L SENSO R
TC
S CONTRO L
VALV E ACTUATO R UNDER-DAS
H FUSE/RELA Y BO X
TC
S SWITC H
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's "yaw" rate

(the turn rate of the vehicle'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's body will exceed the driver'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

Engine Outpu t Contro l
Whe n th e TC S is activated , th e TC S contro l uni t signal s th e TC S contro l valv e actuato r an d PCM . Th e actuato r i s linke d to
th e TC S contro l valv e whic h is normall y returne d to full y ope n positio n b y th e tw o retur n springs .
Althoug h th e throttl e valv e is stil l withi n th e driver' s control , th e engin e outpu t i s relaxe d b y th e TC S contro l valv e an d
PC M to achiev e optimu m traction .
TCS CONTRO L VALV E SENSO R
TCS CONTRO L VALV E
TCS CONTRO L VALV ERETUR N SPRING S
TCS CONTRO L VALV EACTUATO R (D C MOTOR )
DURING NORMA L DRIVING : DURING TC S ACTUATION :
TC S CONTRO L VALV E
TC S CONTRO L VALV E
ACTUATO R (D C MOTOR ) TC
S CONTRO L VALV E
RETUR N SPRING S
TC S ACTUATIO N SIGNA L
FRO M TC S CONTRO L UNI T
ProCarManuals.com

Diagnostic Troubl e Cod e (DTC )
Diagnosti c Troubl e Cod e (DTC ) Indicatio n
1. Connec t th e SC S servic e connecto r t o th e servic e chec k connecto r unde r th e glov e box .
2. Tur n th e ignitio n switc h O N (II) , bu t d o no t star t th e engine .
3. Recor d th e blinkin g frequenc y o f th e TC S indicato r light . Th e blinkin g frequenc y indicate s th e diagnosti c troubl e cod e
(DTC) .
4. Tur n th e ignitio n switc h off , an d remov e th e SC S servic e connector .
NOTE : Th e Malfunctio n Indicato r Lam p (MIL ) wil l sta y o n afte r th e engin e is starte d i f th e SC S servic e connecto r i s con -
nected .
5 . Perfor m th e DT C erasure .
SCS SERVIC E CONNECTO R07PAZ-001010 0
TCS INDICATO R LIGH T
SERVIC E CHEC KCONNECTO R (2P )
DTC Indicatio n Patter n
Tur n th e ignitio n switc h O N (II) . Th e TC S indicato r ligh t come s o n t o chec k th e bulb . D o no t coun t i t a s a DTC .
Th e TC S contro l uni t ca n memoriz e u p to thre e DTCs .
A ne w DT C is no t memorize d agai n whe n th e TC S contro l uni t ha s alread y memorize d th e sam e DTC .
The TC S contro l uni t indicate s th e DT C repeatedl y a t interval s o f 3. 3 seconds .
I f yo u miscoun t th e blinkin g frequenc y o r i f yo u rechec k th e blinkin g frequency , tur n th e ignitio n switc h OF F the n tur n i t
O N (II ) t o cycl e th e TC S indicato r ligh t again .
ProCarManuals.com

Electronic Component s
Steering Angl e Senso r Replacemen t
CAUTION: D o no t damag e o r dro p th e steerin g angl e senso r a s it i s sensitive .
1 . Remov e th e combinatio n switc h (refe r t o sectio n 1 7 in th e '9 5 - '9 8 Acur a 2.5T L servic e manual , P/ N 61SW504) .
2 . Remov e th e circli p an d screw , the n remov e th e steerin g angl e senso r fro m th e combinatio n switch .
3 . Installatio n i s i n th e revers e orde r o f removal .
CAUTION : D o no t appl y an y greas e o r oi l t o th e steerin g angl e sensor .
4 . Perfor m th e steerin g angl e senso r syste m check . SCRE W
STEERING ANGL E SENSO R
COMBINATIO N SWITC H
CANCE L CA M
WAV E WASHE R
SPRING
LOWER COVE R
NOTE: Whe n reassembling , alig n th e tab s o f th e join t an d
cance l ca m to th e sli t o f th e steerin g angl e sensor .
Steering Angl e Senso r Syste m Chec k
1. Star t th e engine .
2 . Pus h th e TC S switc h thre e time s withi n thre e seconds .
NOTE: Alway s maintai n th e sam e numbe r o f rotations .
3. Slowl y tur n th e steerin g whee l fro m clockwis e mor e tha n 1. 5 turns .
NOTE :
• Star t checkin g afte r th e steerin g whee l move s a t leas t 1. 5 turns .
• Tur n th e steerin g whee l slowly , n o faste r tha n on e tur n in fou r seconds .
4 . Pus h th e TC S switc h twic e withi n thre e seconds .
NOTE : Alway s maintai n th e sam e numbe r o f rotations .
5 . Slowl y tur n th e steerin g whee l counterclockwise , an d chec k th e numbe r o f time s th e TC S indicato r ligh t flashe s afte r
th e whee l ha s move d approximatel y on e turn .
NOTE :
• Star t countin g afte r th e steerin g whee l move s on e turn .
• Tur n th e steerin g whee l slowly , n o faste r tha n on e tur n i n fou r seconds .
Standar d numbe r o f time s th e TC S indicato r ligh t flashes : 2 time s ('9 6 model )
: 4 time s ('9 7 model )
6 . I f ther e is a n abnormality , chec k th e troubleshooting flowchart (se e pag e 19-126 ).
JOIN T
CIRCLI P
ProCarManuals.com

Troubleshooting

Radiator Fan Control Module Input Tests

NOTE: Perform the following tests with the radiator fan control module 8P connector connected, the ignition switch ON (II),

and the A/C switch OFF. If you find the cause of a problem, correct it before you continue.

RADIATOR FAN CONTROL MODULE 8P CONNECTOR

WIRE SIDE OF FEMALE TERMINALS

Terminal

No.

4

6

7

2

3

1

8

5
Wire

color

BLK

WHT/GRN

BLK/YEL

BLK/YEL

YEL/WHT

YEL

LT

GRN/YEL

ORN
Test condition

Check for voltage to body

ground.

Check for battery voltage:

Check for battery voltage:

Ignition switch - ON (II)

Check for battery voltage:

Ignition switch - ON (II)

Check for battery voltage:

Ignition switch - ON (II)

Check for battery voltage:

Ignition switch - ON (II)

Connect to body ground:

Ignition switch - ON (II)

Check for voltage.
Desired results

There should be less

than one volt.

There should be battery

voltage.

Condenser fan and radia-

tor fan should come on.

Approx. 11 V (engine oil

temperature below 198°F

[92°C])
Corrective action if desired results are

not obtained

Repair open to body ground.

Check No. 56 (10 A) fuse in the under-

hood fuse/relay box; if OK, repair open

in the WHT/GRN wire.

Check No. 4* fuse in the under-dash

fuse/relay box; if OK, repair open in the

BLK/YEL wire.

Check No. 7 (7.5 A) fuse in the under-

dash fuse/relay box; if OK, repair open in

the BLK/YEL wire.

Replace the radiator fan control module.

Before you connect the new radiator fan

control module, disconnect both fan

relays. Check for continuity between the

YEL/WHT (or YEL) wire and ground, using

the 20 scale on your ohmmeter. There

should be no continuity. If there is conti-

nuity, the new radiator fan control mod-

ule will be damaged when you connect it.

Check for an open in the LT GRN/YEL

wire between the radiator fan control

module and the condenser fan relay or

the radiator fan relay. If OK, check for an

open in the YEL/WHT wire between the

radiator fan control module and the radi-

ator fan relay, or the YEL wire between

the radiator fan control module and the

condenser fan relay. If OK, test the con-

denser fan relay or the radiator fan relay.

Faulty engine oil temperature switch,

short to body ground, or faulty radiator

fan control module.

*No. 4 (15 A):'96 model

No. 4 (20 A): '97 and '98 modelsProCarManuals.com

A/C System Service

Performance Test

The performance test will help determine if the air con-

ditioner system is operating within specifications.

Use only service equipment that is U.L.-listed and is cer-

tified to meet the requirements of SAE J2210 to remove

HFC-134a (R-134a) from the air conditioner system.

CAUTION: Exposure to air conditioner refrigerant and

lubricant vapor or mist can irritate eyes, nose and

throat. Avoid breathing the air conditioner refrigerant

and lubricant vapor or mist.

If accidental system discharge occurs, ventilate work

area before resuming service.

R-134a service equipment or vehicle air conditioner sys-

tems should not be pressure tested or leak tested with

compressed air.

Some mixtures of air and R-134a have been

shown to be combustible at elevated pressures and can

result in fire or explosion causing injury or property

damage. Never use compressed air to pressure test R-

134a service equipment or vehicle air conditioner sys-

tems.

Additional health and safety information may be obtained

from the refrigerant and lubricant manufacturers.

1.

2.
Connect a R-134a refrigerant Recover/Recycling/

Charging System to the vehicle, as shown, follow-

ing the equipment manufacturer's instructions.

Insert a thermometer in the center vent outlet.

Determine the relative humidity and air tempera-

ture.
Recovery/Recycling/Charging System

HIGH-PRESSURE

SIDE

LOW-PRESSURE

SIDE

3. Test conditions:

Avoid direct sunlight.

Open hood.

Open front doors.

Set the temperature control dial on MAX COOL,

the mode control switch on VENT and the recir-

culation control switch on RECIRCULATE.

Turn the A/C switch on, and the fan switch on

MAX.

Run the engine at 1,500 rpm.

No driver or passengers in vehicle

4. After running the air conditioning for 10 minutes

under the above test conditions, read the delivery

temperature from the thermometer in the dash vent

and the high and low system pressure from the A/C

gauges.ProCarManuals.com