check engine ACURA TL 1995 Service Manual Online

Troubleshooting Precautions

ABS Indicator Light:

The ABS indicator light comes on for three seconds and then goes off when the control unit detects no problem during the

initial diagnosis right after the engine starts. However, the ABS indicator light can stay on for up to 40 seconds when the

control unit starts to check for pump overrun, etc. during the initial diagnosis. The ABS indicator light comes on, and the

ABS control unit memorizes the diagnostic trouble code (DTC) under certain conditions.

The parking brake is applied for more than 30 seconds while the vehicle is being driven. (DTC 2-1)

The transmission downshifted excessively. (DTC 4-1, 4-2)

The vehicle loses traction, and the front wheels spin for more than one minute when starting from a stuck condition on

a muddy, snowy, or sandy road. (DTC 4-8)

Tire adhesion is lost due to excessive cornering speed. (DTC 5, 5-4, 5-8)

The vehicle is driven on an extremely rough road. (DTC 8-1)

The vehicle is interfered by strong radio waves (noise), for example, illegal radio, etc. (DTC 8-2)

NOTE: If there is any trouble in the system, the ABS indicator light comes on during driving.

Diagnostic Trouble Code (DTC):

When the control unit detects a problem and the ABS indicator light comes on, the control unit memorizes the DTC.

The control unit has three memory registers. When a problem occurs, the control unit stores the DTC in the first memory

register. If another problem occurs, or the same problem occurs again, the control unit moves the first DTC to the next

memory register, and stores the second DTC in the first register. If there's a third problem occurrence, the two existing

DTCs are moved up one register, and the third DTC is stored in the first register. If problems continue to occur, the oldest

problem is moved out of the last register and lost, and the most recent problem is stored in the first register. When the

same problem occurs three times, the same DTC is stored in all memory registers. (Refer to the Symptom-to-System

Chart for diagnostic period.)

The most recent DTC is indicated first, and the oldest DTC is indicated last.

The DTCs are erased from the control unit when the ABS control unit +B2 power supply or connector is disconnected.

The control unit's memory can be erased by disconnecting the ABS B2 fuse for more than three seconds.

Self-diagnosis:

There are three self-diagnosises described below.

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

Regular diagnosis: Continuously performed (under some conditions) after the ABS indicator light goes off until the

engine stops.

Individual part/system diagnosis: Diagnosis about a specific part/system under its operating conditions.

The CPU (central processing unit) controls the following when it detects a problem during self-diagnosis:

Turns the ABS indicator light ON.

Turns the front and rear fail-safe relays off.

Stops the ABS control.

Stops the ABS pump. (The pump may work under some conditions.)

After the DTC is stored in the control unit, the CPU stops self-diagnosis.ProCarManuals.com

Kickback and Pump Operation:

When the engine is started, the ABS control unit begins the initial diagnosis and operates the solenoid valve one time.

The kickback may be felt when the brake pedal is depressed.

When the ABS control unit detects the pressure switch OFF signal during the initial diagnosis, it operates the pump

motor, and performs the pump motor over-run diagnosis and pump motor diagnosis. Therefore, there are two cases

where the pump motor operates or does not operate after the engine is started.

Normally, after the initial diagnosis, the pump motor operates based on the pressure switch signal, regardless of the

vehicle speed.

Troubleshooting:

When two or three DTCs are stored in the control unit, perform troubleshooting for the DTC that appears first.

When a customer's reported problem cannot be verified on the car, ask the customer about the conditions when the

ABS indicator light came ON, and test-drive the car under those conditions, if possible. When the ABS indicator light

does not come ON during the test, check for loose terminals and check by shaking the harnesses and connectors while

following the flowchart.

The connector terminal numbers are viewed from the wire side for the female terminals, and from the terminal side for

the male terminals.

After the repair is completed, test-drive the car and check that the ABS indicator light does not come ON again during

the test. (Refer to the Symptom-to-System Chart for diagnostic period.)ProCarManuals.com

DTC Indication Pattern (When the ABS control unit detected a problem three times.):

Turn the ignition switch ON (II). The ABS indicator light comes on for two seconds to check the bulb.

The ABS control unit indicates the DTC three times.

If you miscount the blinking frequency or if you recheck the blinking frequency, turn the ignition switch OFF then

turn it ON (II) to cycle the ABS indicator light again.

4. Remove the SCS service connector.

NOTE: The Malfunction Indicator Lamp (MIL) will stay on after the engine is started if the SCS service connector is

connected.

5. Remove the ABS B2 (15 A) fuse in the under-hood ABS fuse/relay box for at least three seconds to erase the ABS con-

trol unit's memory.ProCarManuals.com

ABS Functio n Tes t
Modulato r Functio n Chec k
NOTE : Thi s inspectio n determine s whethe r th e basi c
brake syste m continue s t o operat e normall y whe n th e
modulato r uni t flui d pressur e i s low .
CAUTION :
Thi s inspectio n i s mad e b y relievin g th e high-pres -
sur e flui d i n th e modulato r uni t an d checkin g fo r
brak e operation . Afte r inspection , b e sur e t o ad d
fres h brak e flui d t o th e specifie d leve l o f th e reser -
voir , an d star t th e engin e t o restor e th e AB S t o it s
norma l operatin g condition .
D o no t spil l brak e flui d o n th e car ; i t ma y damag e th e
paint ; i f brak e flui d doe s contac t th e paint , was h i t
of f immediatel y wit h water .
D o no t reus e th e draine d brak e fluid .
D o no t loose n th e relie f plu g o n th e accumulator .
1.Remov e th e bleede r ca p fro m th e maintenanc e
bleede r o n th e modulato r unit .
BLEEDE R CA P
RUBBE R TUB EMODULATO R UNI T
MAINTENANC E BLEEDE R11 N- m (1. 1 kgf-m , 8 Ibf-ft )
2. Attac h a wrenc h t o th e maintenanc e bleeder .
3 . Connec t a rubbe r tub e o f th e appropriat e diamete r
t o th e maintenanc e bleeder , an d se t th e othe r en d o f
th e rubbe r tub e in a suitabl e container .
4 . Whil e holdin g th e rubbe r tub e wit h you r hand , slowl y
loose n th e maintenanc e bleede r 1/ 8 to 1/ 4 tur n t o col -
lec t th e brak e flui d in th e container .
CAUTION : D o no t loose n th e maintenanc e bleede r
to o much . Th e high-pressur e brak e flui d ca n burs t out .
5 . Afte r th e brak e flui d stop s flowin g out , loose n th e
maintenanc e bleede r mor e t o releas e th e pressur e
completely .
6 . Tighte n th e maintenanc e bleede r t o th e specifie d
torque .
7. Rais e th e ca r of f th e ground , an d suppor t i t wit h
safet y stand s (se e sectio n 1 ).
8 .Hav e a n assistan t depres s th e brak e peda l firmly ,
an d chec k tha t th e wheel s d o no t rotate .
9 . Remov e th e cap , an d refil l th e reservoi r t o th e MA X
(upper ) leve l wit h fres h brak e fluid .
NOTE : Pou r th e brak e flui d slowl y s o tha t i t doe s
no t foam , an d wai t fo r a fe w minutes .
10 . Star t th e engin e an d le t i t idl e fo r a minute . Sto p th e
engine .
11 . Chec k th e brak e flui d leve l i n th e reservoir . I t shoul d
b e belo w th e MA X (upper ) leve l line . Refil l th e
reservoi r wit h fres h brak e flui d t o th e MA X leve l lin e
again .
CAPRESERVOI R
MAX (UPPER ) LEVE RLINE
MIN (LOWER )LEVEL LIN E
12. Afte r inspection , star t th e engin e an d mak e sur e
tha t th e AB S indicato r ligh t goe s off .
ProCarManuals.com

Modulator Uni t
Removal/Installatio n (cont'd )
Installation :
1 . Chec k whethe r th e brak e flui d leve l i n th e reservoi r
i s a t th e MA X (upper ) lever . I f leve l i s low , ad d fres h
brak e flui d t o th e MA X (upper ) level .
CAP
MA X (UPPER ) LEVE L
LIN E
2. Befor e installin g th e modulato r uni t o n th e car , b e
sur e t o blee d th e ai r fro m th e suctio n por t i n th e
modulato r uni t b y leanin g th e modulato r uni t t o on e
sid e slowl y (abou t 4 5 degrees ) a s shown .
RESERVOI R
SUCTION POR T
Abou t 4 5 degree s
MODULATO R UNI T
CAUTION : Whe n installin g th e modulato r unit , b e
carefu l no t t o tur n i t upside-dow n o r lea n i f exces -
sively.
3. Instal l th e modulato r uni t i n th e revers e orde r o f
removal .
NOTE : Chec k th e letter s stampe d o n th e modulato r
body , an d connec t th e brak e pipe s properly .
Tighte n th e flar e nut s t o 1 9 N- m (1. 9 kgf-m , 1 4 Ibf-ft) .
Connec t th e lin e Connec t th e lin e Connec t th e lin e
fro m th e right-rea r fro m th e left-rea r fro m th e right-fron t
whee l t o "RR" . whee l t o "RL" . whee l t o "FR" .
Connec t th e lin e
fro m th e left-fron t
wheel t o "FL" .
MODULATO R UNI T
Lin e fro m th e Lin e fro m th e
maste r cylinde r maste r cylinde r
secondar y sid e primar y sid e
4. Star t th e engine and le t i t idl e fo r a minute .
Chec k that :
ABS indicato r ligh t i s off .
Brak e flui d i s no t leakin g fro m th e brak e pip e
joints .
5. Sto p th e engine .
6 . Chec k whethe r th e brak e flui d leve l i n th e reservoi r
i s a t th e MA X (upper ) level . I f leve l i s low , ad d fres h
flui d unti l th e reservoi r i s refille d t o th e MA X (upper )
level.
7. Blee d ai r fro m th e brak e syste m (se e pag e 19-7 ).
8 . Chec k th e AB S functio n usin g th e AL B checke r (se e
pag e 19-112 ).
ProCarManuals.com

Modulator Unit

Removal/Installation

CAUTION:

Do not spill brake fluid on the vehicle; it may damage the paint; if brake fluid does contact the paint, wash it off

immediately with water.

Take care not to damage or deform the brake lines during removal and installation.

To prevent the brake fluid from flowing, plug and cover the hose ends and joints with a shop towel or equivalent

material.

NOTE: Tighten the flare nuts to 15 N-m (1.5 kgf-m, 11 Ibf-ft).

Removal

1. Disconnect the modulator unit 10P and pump motor 2P connectors.

2. Remove the proportioning control valve.

3. Disconnect the brake lines, then remove the modulator unit.

Installation

1. Install the modulator unit, then connect the brake lines.

2. Install the proportioning control valve.

3. Connect the modulator unit 10P and pump motor 2P connectors.

4. Bleed the brake system, starting with the front wheels.

5. Start the engine, and check that the ABS indicator light goes off.

6. Test-drive the vehicle, and check that the ABS indicator light does not come on.

MODULATOR UNIT

10P CONNECTOR
From right-front

From left-front

PUMP MOTOR

2P CONNECTOR

6 mm BOLT

9.8 N-m (1 .0 kgf-m, 7 Ibf-ft) PROPORTIONING

CONTROL

VALVE

6 mm NUT

9.8 N-m (1.0 kgf-m, 7 Ibf-ft)

BRACKET
RUBBER MOUNT

MODULATOR UNIT

8 mm BOLT

22 N-m (2.2 kgf-m, 16 Ibf-ft)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

YEL/BLK

YEL/WHT

YEL

LT

GRN/YEL

WHT/GRN
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

coolant temperature

below 207°F [97°C])
Corrective action if desired results are

not obtained

Repair open to body ground.

Check No. 39 (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. 8 (7.5 A) fuse in the under-

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

the YEL/BLK 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 k 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 con-

denser fan relay, or the YEL wire between

the radiator fan control module and the

radiator fan relay. If OK, test the con-

denser fan relay or the radiator fan relay.

Faulty engine coolant temperature (ECT)

switch B, short to body ground, or faulty

radiator fan control module.

* No.4 (15 A): '95 and '96 models

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

Troubleshooting

Tips and Precautions

Before Troubleshooting

Check applicable fuses in the appropriate fuse/relay

box.

Check the battery for damage, state of charge, and

clean and tight connections.

Check the alternator belt tension.

CAUTION:

Do not quick-charge a battery unless the battery

ground cable has been disconnected, otherwise you

will damage the alternator diodes.

Do not attempt to crank the engine with the battery

ground cable loosely connected or you will severely

damage the wiring.

Handling Connectors

Make sure the connectors are clean and have no loose

wire terminals.

Make sure multiple cavity connectors are packed with

grease (except waterproof connectors).

All connectors have push-down release type locks.

LOCKING TAB

Some connectors have a clip on their side used to

attach them to a mount bracket on the body or on

another component. This clip has a pull type lock.

Some mounted connectors cannot be disconnected

unless you first release the lock and remove the con-

nector from its mount bracket.

LOCKING

PAWL ON

OTHER

HALF OF

CONNECTOR
Pull to

disengage

BRACKET
Never try to disconnect connectors by pulling on

their wires; pull on the connector halves instead.

Always reinstall plastic covers.

Before connecting connectors, make sure the termi-

nals are in place and not bent.

BENT TERMINAL

Check for loose retainer and rubber seals.

RETAINER
RUBBER SEAL RETAINER

The backs of some connectors are packed with

grease. Add grease if necessary. If the grease is con-

taminated, replace it.
LOCKING TABProCarManuals.com

Check for Wear and Damage

The starter should crank the engine smoothly and steadily.

If the starter engages, but cranks the engine erratically,

remove it, and inspect the starter drive gear and torque

converter ring gear for damage.

Check the drive gear overrunning clutch for binding or

slipping when the armature is rotated with the drive

gear held. If the clutch is damaged, replace the clutch

assembly.

Check Cranking Voltage and Current Draw

Cranking voltage should be no less than 8.5 volts.

Current draw should be no more than 380 amperes.

If cranking voltage is too low, or current draw too high,

check for:

Dead or low battery

Open circuit in starter armature commutator segments

Starter armature dragging

Shorted armature winding

Excessive drag in engine

Check Cranking rpm

Engine speed during cranking should be above 100 rpm.

If speed is too low, check for:

Loose battery or starter terminals

Excessively worn starter brushes

Open circuit in commutator segments

Dirty or damaged helical spline or drive gear

Defective drive gear overrunning clutch

Check Starter Disengagement

With the shift lever in turn the ignition switch to

"START (III)", and release to "ON (II)". The starter drive

gear should disengage from the drive plate/ring gear

when you release the key.

If the drive gear hangs up on the drive plate/ring gear,

check for:

• Solenoid plunger and switch malfunction

• Dirty drive gear assembly or damaged overrunning

clutchProCarManuals.com

Distributor Top End Inspection

1. Check for rough or pitted rotor and cap terminals.

2. Scrape or file off the carbon deposits. Smooth the

rotor terminal with an oil stone or #600 sandpaper if

rough.

ROTOR

TERMINAL
CAP TERMINAL

CARBON

POINT

3. Check the distributor ignition (Dl) cap for cracks, wear,

and damage. If necessary, clean or replace it.
Noise Condenser Capacity Test

1. Use a commercially available condenser tester.

Connect the condenser tester probes and measure

the condenser capacity.

Condenser capacity: 0.47 ± 0.09 microfarads

POSITIVE TERMINAL

BODY GROUND

(Negative)

NOTE: The noise condenser is intended to reduce

ignition noise. However, condenser failure may cause

the engine to stop running.

2. If not within the specifications, replace the noise con-

denser.ProCarManuals.com